Florence Cohen (born July 28, 1917), a pioneer public sector union leader with the Rural Electrification Administration from 1936 to 1943 and a longtime Philadelphia civic, political and feminist leader, and Philadelphia city official was born in New York City on July 28, 1917. Her father Harry was a garment maker and her mother was a housewife who died in the Influenza Epidemic of 1918, also known as the Spanish Flu. She was then raised by her mother's mother, an immigrant from the Russian Pale of Settlement, as the youngest of nine children.
Biography
She began working for the Rural Electrification Administration as a secretary under her maiden name of Florence Herzog in 1936. Her note-taking skills led her to become secretary of her union local for Rural Electrification workers shortly after she was hired. She enrolled in George Washington University as an evening student, earned a degree in Economics and ultimately became a statistician for the REA.
She was a small part of a massive national effort located within the U.S. Department of Agriculture to provide rural electrification. In 1930 , only 13% of all farms had electricity, but by 1950, 93% of all farms had electricity. Her experience with the REA would typify her life: she had the capacity to identify with people with problems she had not personally experienced. In 1994, Congress would convert the Rural Electrification Administration into the Rural Utilities Service.
She worked closely with David Cohen, an agency attorney elected as President of her labor union in 1938, and married him in 1946 when he returned to the United States after service as a U.S. Army staff sergeant in New Guinea during World War II.
She was working as a union organizer at the time of the birth of her first child in 1949. While raising four children, all of whom would follow her into community activities and public service-Mark, Denis, Sherrie, and Judy-she earned a master's degree in education at the University of Pennsylvania. She would later become an administrator in the epidemiology program at the University of Pennsylvania Medical School, after having taught in the Philadelphia School District and at the Community College of Philadelphia.
Her child rearing years were years of great activism. She and her husband hosted meetings of the Northwest Philadelphia Chapter of the American Jewish Congress at their home, and she recruited people to lobby the Pennsylvania General Assembly to enact fair housing legislation.
She was a co-founder of the Ogontz Area Neighbors Association in 1959, was its first long-serving President, and a board member for many years after her last term as President was completed. The Ogontz Area Neighbors Association is still active and will be celebrating its 50th anniversary in 2009.
She co-founded and was the first chair of the 17th Ward Women's Democratic Club. She co-founded and was the first chair of the New Democratic Coalition of Philadelphia, a leader of the Philadelphia political reform movement in the 1970s. She served as a Democratic committeewoman in the 17th Ward, 20th Division and as a delegate to the 1996 Democratic National Convention.
She was an early member of the Philadelphia chapter of the National Organization of Women and the Philadelphia Chapter of the Women's Political Caucus.
After her son Mark B. Cohen's election to the Pennnsylvania legislature in 1974, Florence Cohen encouraged fellow caucus member Ruth Harper, a modeling school owner, to run for the Pennsylvania House of Representatives in 1976. Harper defeated an incumbent and serve for 16 years, during which time she was a champion of women's rights and a member of the Democratic National Committee.
Florence Cohen's activism often got her husband involved as well. David Cohen handled his first zoning on a pro-bono basis for the Ogontz Area Neighbors Association in 1960 and continued to be active on pro-bono cases for neighborhood associations around the city until his death in 2005.
She was an active volunteer for her husband when he served as the 8th District City Councilman from 1968 through 1971, writing legislation and resolutions and meeting with community organizations. For the first 17 years of his 26 year tenure as Councilman at Large, she served as his Chief of Staff, earning widespread praise for her performance in that role.
Five months after her retirement from the Philadelphia City Council staff, he became seriously ill, and she spearheaded the gaining of appropriate medical treatment for his recovery, and assisted him as a volunteer for the next nine years in performing Council duties of constituent advocacy, legislative oversight, and passage of legislation.
In their last joint public appearance, receiving the 17th Annual awards from the Bread and Roses foundation on September 12, 2005, he praised her and said "When people say Dave and Florence, they mean Florence and Dave. She was my teacher...."
After his death at the age of 90 on October 3, 2005, she became deeply involved in preserving his legacy. Like her husband a strong opponent of ageism, she sought, at age 88, Democratic Party support to fill out his unexpired term. After another longterm aide of Councilman Cohen, Bill Greenlee, 53, the Democratic Leader of the 15th Ward, whose job responsibilities in the field of constituent service kept him in close touch with ward leaders and other community leaders, was selected by the Democratic ward leaders to fill out the term in 2006, she strongly endorsed his general election candidacy.
She attended and spoke at ceremonies announcing awards in Councilman Cohen's name by the Philadelphia Cultural Fund and the Community High School of Philadelphia, Philadelphia's first charter school. She pledged funds for annual awards to top male and female students at the Joseph Pennell Elementary School, which all four of her children had attended and where she had been active in the Home and School Association. She determined that her husband's gravestone contained the words "conscience of the city."
Since 2004 an independent living resident of the Watermark (formerly Logan Square East), a multi-level senior citizens housing complex located in Center City, Philadelphia, she joined her fellow residents in numerous activities, including attending a 2006 protest demonstration called by the American Civil Liberties Union against President George W. Bush's policies.
Before her 90th birthday in 2007, she continued to be active. She helped form the local chapter of the national organization Grannies for Peace, and served as its first President. She was elected an officer (2nd Vice President) of the Watermark Residents Association. At the annual swearing-in ceremonies for the officers of the Watermark Residents Association, held in April, 2007, she arranged for the oath of office for each officer to be administered by her son, Philadelphia Common Pleas Court Judge Denis P. Cohen.
She became President of the Watermark Residents Association in November, 2007, after the President resigned to move out of the building and the first Vice-President declined to be promoted to President.
Biography
She began working for the Rural Electrification Administration as a secretary under her maiden name of Florence Herzog in 1936. Her note-taking skills led her to become secretary of her union local for Rural Electrification workers shortly after she was hired. She enrolled in George Washington University as an evening student, earned a degree in Economics and ultimately became a statistician for the REA.
She was a small part of a massive national effort located within the U.S. Department of Agriculture to provide rural electrification. In 1930 , only 13% of all farms had electricity, but by 1950, 93% of all farms had electricity. Her experience with the REA would typify her life: she had the capacity to identify with people with problems she had not personally experienced. In 1994, Congress would convert the Rural Electrification Administration into the Rural Utilities Service.
She worked closely with David Cohen, an agency attorney elected as President of her labor union in 1938, and married him in 1946 when he returned to the United States after service as a U.S. Army staff sergeant in New Guinea during World War II.
She was working as a union organizer at the time of the birth of her first child in 1949. While raising four children, all of whom would follow her into community activities and public service-Mark, Denis, Sherrie, and Judy-she earned a master's degree in education at the University of Pennsylvania. She would later become an administrator in the epidemiology program at the University of Pennsylvania Medical School, after having taught in the Philadelphia School District and at the Community College of Philadelphia.
Her child rearing years were years of great activism. She and her husband hosted meetings of the Northwest Philadelphia Chapter of the American Jewish Congress at their home, and she recruited people to lobby the Pennsylvania General Assembly to enact fair housing legislation.
She was a co-founder of the Ogontz Area Neighbors Association in 1959, was its first long-serving President, and a board member for many years after her last term as President was completed. The Ogontz Area Neighbors Association is still active and will be celebrating its 50th anniversary in 2009.
She co-founded and was the first chair of the 17th Ward Women's Democratic Club. She co-founded and was the first chair of the New Democratic Coalition of Philadelphia, a leader of the Philadelphia political reform movement in the 1970s. She served as a Democratic committeewoman in the 17th Ward, 20th Division and as a delegate to the 1996 Democratic National Convention.
She was an early member of the Philadelphia chapter of the National Organization of Women and the Philadelphia Chapter of the Women's Political Caucus.
After her son Mark B. Cohen's election to the Pennnsylvania legislature in 1974, Florence Cohen encouraged fellow caucus member Ruth Harper, a modeling school owner, to run for the Pennsylvania House of Representatives in 1976. Harper defeated an incumbent and serve for 16 years, during which time she was a champion of women's rights and a member of the Democratic National Committee.
Florence Cohen's activism often got her husband involved as well. David Cohen handled his first zoning on a pro-bono basis for the Ogontz Area Neighbors Association in 1960 and continued to be active on pro-bono cases for neighborhood associations around the city until his death in 2005.
She was an active volunteer for her husband when he served as the 8th District City Councilman from 1968 through 1971, writing legislation and resolutions and meeting with community organizations. For the first 17 years of his 26 year tenure as Councilman at Large, she served as his Chief of Staff, earning widespread praise for her performance in that role.
Five months after her retirement from the Philadelphia City Council staff, he became seriously ill, and she spearheaded the gaining of appropriate medical treatment for his recovery, and assisted him as a volunteer for the next nine years in performing Council duties of constituent advocacy, legislative oversight, and passage of legislation.
In their last joint public appearance, receiving the 17th Annual awards from the Bread and Roses foundation on September 12, 2005, he praised her and said "When people say Dave and Florence, they mean Florence and Dave. She was my teacher...."
After his death at the age of 90 on October 3, 2005, she became deeply involved in preserving his legacy. Like her husband a strong opponent of ageism, she sought, at age 88, Democratic Party support to fill out his unexpired term. After another longterm aide of Councilman Cohen, Bill Greenlee, 53, the Democratic Leader of the 15th Ward, whose job responsibilities in the field of constituent service kept him in close touch with ward leaders and other community leaders, was selected by the Democratic ward leaders to fill out the term in 2006, she strongly endorsed his general election candidacy.
She attended and spoke at ceremonies announcing awards in Councilman Cohen's name by the Philadelphia Cultural Fund and the Community High School of Philadelphia, Philadelphia's first charter school. She pledged funds for annual awards to top male and female students at the Joseph Pennell Elementary School, which all four of her children had attended and where she had been active in the Home and School Association. She determined that her husband's gravestone contained the words "conscience of the city."
Since 2004 an independent living resident of the Watermark (formerly Logan Square East), a multi-level senior citizens housing complex located in Center City, Philadelphia, she joined her fellow residents in numerous activities, including attending a 2006 protest demonstration called by the American Civil Liberties Union against President George W. Bush's policies.
Before her 90th birthday in 2007, she continued to be active. She helped form the local chapter of the national organization Grannies for Peace, and served as its first President. She was elected an officer (2nd Vice President) of the Watermark Residents Association. At the annual swearing-in ceremonies for the officers of the Watermark Residents Association, held in April, 2007, she arranged for the oath of office for each officer to be administered by her son, Philadelphia Common Pleas Court Judge Denis P. Cohen.
She became President of the Watermark Residents Association in November, 2007, after the President resigned to move out of the building and the first Vice-President declined to be promoted to President.
The "Feast or Fired" match was created by James Cornette of Total Nonstop Action wrestling in 2007. It is when there are four suitcases hanging on four poles on opposite corners of the ring, which is six-sided. In three of the suitcases are title shots, one is for the TNA world heavyweight championship, another is for the TNA world tag team championship and the other is for the x-division championship. But here is the catch, in the last suitcase is a certificate that says "Your fired" and that person will be removed from the roster, never to return again. So far, there has been only one match which took place at the turning point pay-per-view. The people who got the cases were... Scott Steiner, B.G James, Senshi(lost the case to Christopher Daniels)and Petey Williams. After Steiner won a fatal four way match, he had three options, he could trade in his case for 50000 dollars, he could swap cases with someone else, or he could just drop out entirely. Steiner chose to swap cases with Petey Williams, it would later be revealed that Steiner's case contained the TNA heavyweight title shot, which Petey Williams received because Steiner chose to switch cases just moments before.
Supposedly, if you get the fired slip you are really fired, but it could just be part of a storyline of TNA.
Then the next case to be revealed was B.G James, who had been arguing with tag team partner and long time friend Kip James about two things, one was if B.G got the tag title shot, he had said his mind was not made up as to who would be his partner. Kip had actually gotten the case in the match, but then tossed it outside the ring to partner B.G, which caused controversy as to who the case really belonged to. In the end, B.G got rightful ownership of the case and it would later be revealed that he had earned a tag title match, then he said that his partner was still undecided. This left only Christopher Daniels and Scott Steiner and what was left was the x division title and the slip that says your fired.
This is it, it would be revealed who would get the x division title match and who would be fired, first interviewer Jeremy Borash went through the careers and championship reigns of both Steiner and Daniels alike. Then it would be revealed that Christopher Daniels was fired and Scott Steiner got the x division title shot. For those who dont know, Christopher Daniels "the fallen angel" is a TNA original, meaning he was one of the first wrestlers to ever be in TNA wrestling. He was very emotional as he left the "Impact Zone" for the final time.
Now for most people reading this article that prefer to watch wwe, give TNA a chance because they do unbelievable things in the ring.
REFERENCES
www.tnawrestling.com
Supposedly, if you get the fired slip you are really fired, but it could just be part of a storyline of TNA.
Then the next case to be revealed was B.G James, who had been arguing with tag team partner and long time friend Kip James about two things, one was if B.G got the tag title shot, he had said his mind was not made up as to who would be his partner. Kip had actually gotten the case in the match, but then tossed it outside the ring to partner B.G, which caused controversy as to who the case really belonged to. In the end, B.G got rightful ownership of the case and it would later be revealed that he had earned a tag title match, then he said that his partner was still undecided. This left only Christopher Daniels and Scott Steiner and what was left was the x division title and the slip that says your fired.
This is it, it would be revealed who would get the x division title match and who would be fired, first interviewer Jeremy Borash went through the careers and championship reigns of both Steiner and Daniels alike. Then it would be revealed that Christopher Daniels was fired and Scott Steiner got the x division title shot. For those who dont know, Christopher Daniels "the fallen angel" is a TNA original, meaning he was one of the first wrestlers to ever be in TNA wrestling. He was very emotional as he left the "Impact Zone" for the final time.
Now for most people reading this article that prefer to watch wwe, give TNA a chance because they do unbelievable things in the ring.
REFERENCES
www.tnawrestling.com
ShapeIdeas is a knowledge and concept mapping tool for the education sector. ShapeIdeas includes support for BPMN (Business Process Modeling Notation), UML (Unified Modeling Language) and Mind Mapping as well as inking for use on Tablet PCs and interactive whiteboards.
History
The original version of ShapeIdeas was released as ShapeIdeas Sneaky Peek 2006 in late December 2005.
The next version of ShapeIdeas 2008 is targeted for release on January 14, 2008.
Features
ShapeIdeas features support for two major modeling 'languages' - Business Process Modelling Notation, and Unified Modeling Language, to simplify the creation of process models. It also supports Inking, in the sense that you can 'draw' or write directly into the 'whiteboard', and contains a web browser, for the gathering of external information.
Database Support
The original release of ShapeIdeas Sneaky Peek 2006 only had support for the Microsoft SQL Server 2005 database. However, ShapeIdeas 2008 is planned to support Microsoft SQL Server 2005, Microsoft Access 2003 and 2007 databases, MySQL 4 and 5, and PostGres SQL. Support for the ShapeIdeas proprietary format, ShapeIdeas Information eXchange (.SIX files), which is based upon SQLite, will also be supported.
Currently, there is no way to transfer a database into a different format (eg from Microsoft Access to MySQL). However, this a feature planned for future releases. This feature will be delivered by allowing a ShapeIdeas Repository to be exported to a set of XML files ready for re-importation into another format.
History
The original version of ShapeIdeas was released as ShapeIdeas Sneaky Peek 2006 in late December 2005.
The next version of ShapeIdeas 2008 is targeted for release on January 14, 2008.
Features
ShapeIdeas features support for two major modeling 'languages' - Business Process Modelling Notation, and Unified Modeling Language, to simplify the creation of process models. It also supports Inking, in the sense that you can 'draw' or write directly into the 'whiteboard', and contains a web browser, for the gathering of external information.
Database Support
The original release of ShapeIdeas Sneaky Peek 2006 only had support for the Microsoft SQL Server 2005 database. However, ShapeIdeas 2008 is planned to support Microsoft SQL Server 2005, Microsoft Access 2003 and 2007 databases, MySQL 4 and 5, and PostGres SQL. Support for the ShapeIdeas proprietary format, ShapeIdeas Information eXchange (.SIX files), which is based upon SQLite, will also be supported.
Currently, there is no way to transfer a database into a different format (eg from Microsoft Access to MySQL). However, this a feature planned for future releases. This feature will be delivered by allowing a ShapeIdeas Repository to be exported to a set of XML files ready for re-importation into another format.
The Birchler Lab originally began at Harvard University in Cambridge, MA. In 1993, the Birchler Lab moved to its current location in 117 Tucker Hall on the campus of the University of Missouri–Columbia. The lab is run by Dr. James A. Birchler.
Research Overview
Their longest standing research area has been how changes in chromosomal dosage affect gene expression and the organism. The results indicate that most regulatory processes in multicellular eukaryotes have evolved to be expressed at a level and to operate in such a manner that they are rate limiting on phenotypic characteristics. This property of regulatory mechanisms has implications for a number of genetic phenomena as described below.
Both positive and negative dosage effects operate, although the latter are in the majority. One dose of a chromosome arm often increases target gene expression throughout the genome approximately two-fold relative to the normal diploid. The corresponding three doses can reduce gene expression to a lower limit of two thirds. If such modulation is produced by a chromosomal arm and it has an effect on a target gene varied on the same segment, the change in structural gene dosage is cancelled by this “inverse dosage effect” and dosage compensation results.
They are interested in how dosage dependent regulatory genes control the process of X chromosomal dosage compensation in Drosophila. Their recent work suggests that as the heteromorphic sex chromosomes have evolved, a redistribution of a histone acetylase has occurred to modify how the regulatory dosage effects of the single X in males alter target gene expression. The acetylase is sequestered from the autosomes to prevent the increased expression expected from the prevalence of negatively acting dosage regulators. When the complex is genetically destroyed, the acetylase returns to the autosomes and gene expression increases.
They have also found that hybrid vigor (heterosis) is apparently controlled by dosage dependent regulatory genes. Triploid inbreds and hybrids were produced and compared to diploid inbreds and hybrids. In the triploid situation, there are two types of hybrids (AAB and ABB). When measures of hybrid vigor were applied, the two types differed, indicating an influence of allelic dosage. Preliminary tests of gene expression of randomly selected genes show that hybrids exhibit increased or decreased gene expression per cell. The results have led us to the model that heterosis is a reflection of the fact that most regulatory processes are dosage dependent and that the vast majority of these genes act negatively. If they work less efficiently in hybrids, most target gene expression would be increased.
The lab also studies dispersed transgene silencing (cosuppression) in Drosophila. One type involves a transcriptional process in which the silenced transgenes are associated with the Polycomb group of repressive chromatin proteins. The second involves a posttranscriptional RNA turnover mechanism that possesses the molecular hallmarks characteristic of RNA interference. These mechanisms most likely exist as a genomic defense against transposon mobility and as a cellular shield against viruses. Recent studies in our lab have demonstrated that RNAi machinery is needed for Polycomb dependent transcriptional silencing as well as for proper heterochromatin formation.
Several years ago the laboratory cloned a repeat associated with the maize supernumerary chromosome centromere. Critical regions of this centromere have been defined that permit high fidelity of meiotic transmission. Current studies are involved with understanding the structure of the centromere repeats and their evolution. Also, we are in the process of using these fragments to attempt construction of maize artificial chromosomes, for which we are developing a wide variety of vectors and approaches. As an alternative, we have generated numerous minichromosomes containing little more than the centromere of the supernumerary chromosome, which could be purified and used in constructing yet a different type of vector. The eventual development of artificial chromosome technology will permit the directed study of the components needed for chromosomal behavior as well as many industrial applications. The ability to introduce complete biochemical pathways might confer new properties to the target plant or allow plants to be used as biological factories for the economical production of a desired end-product.
Lab Members - Current and Past
* James Birchler - Principal investigator
*Don Auger - Postdoctoral researcher
*Matthew Bauer - Graduate Student
*Utpal Bhadra - Postdoctoral researcher
*Manika Pal Bhadra - Postdoctoral researcher
*Jenny Cooper - Graduate Student
*Doug Davis
*Tatiana Danilova - Postdoctoral researcher
*Christopher Della Vedova - Graduate Student
*Mei Guo - Postdoctoral researcher
*Akio Kato - Postdoctoral researcher
*Etienne Kaszas
*Harsh Kavi - Graduate Student
*Jonathan Lamb - Graduate Student
*Rick Masonbrink - Graduate Student
*Peggy Northup - Lab Technician
*Tara Phelps-Dur - Graduate Student
*Brent Page - Graduate Student
*James Theuri - Postdoctoral researcher
Publications
For a list of current published research articles, please click on [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?dbpubmed&cmdSearch&itoolpubmed_AbstractPlus&term%22Birchler+JA%22%5BAuthor%5D here]
*Leonard Rabinow and James A. Birchler, 1989. A dosage sensitive modifier of retrotransposon induced alleles of the white locus of Drosophila. The EMBO Journal 8: 879-890.
*James A. Birchler, John C. Hiebert and Leonard J. Rabinow, 1989. Interaction of the mottler of white with transposable element alleles at the white locus in Drosophila melanogaster. Genes and Development 3: 73-84.
*Mei Guo and James A. Birchler, 1994. Trans-acting dosage effects on the expression of model gene systems in maize aneuploids. Science 266: 1999-2002.
*Mei Guo, Doug Davis and James A. Birchler, 1996. Dosage effects on gene expression in a maize ploidy series. Genetics 142: 1349-1355.
*James A. Birchler, 1996. X chromosome dosage compensation in Drosophila. Science 272: 1190.
*Etienne Kaszas and James A. Birchler, 1996. Misdivision analysis of centromere structure in maize. EMBO Journal 15: 5246-5255.
*Manika Pal-Bhadra, Utpal Bhadra and James A. Birchler, 1997. Cosuppression in Drosophila: gene silencing of Alcohol dehydrogenase by white-Adh transgenes is Polycomb dependent. Cell 90: 479-490.
*Manika Pal Bhadra, Utpal Bhadra and James A. Birchler, 1999. Cosuppression of non-homologous transgenes in Drosophila involves mutually related endogenous sequences. Cell 99: 35-46.
*Brent T. Page, Michael K. Wanous and James A. Birchler, 2001. Characterization of a maize chromosome 4 centromeric sequence: evidence for an evolutionary relationship with the B chromosome centromere. Genetics 159: 291-302.
*Manika Pal Bhadra, Utpal Bhadra and James A. Birchler, 2002. RNAi related mechanisms affect both transcriptional and post-transcriptional transgene silencing in Drosophila. Molecular Cell 9: 315-327.
*Cathy X. Zhong, Joshua B. Marshall, Christopher Topp, Rebecca Mroczek, Akio Kato, Kiyotaka Nagaki, James A. Birchler, Jiming Jiang and R. Kelly Dawe, 2002. Centromeric retroelements and satellites interact with maize kinetochore protein CENH3. The Plant Cell 14: 2825-2836.
*Manika Pal Bhadra, Boris A Leibovitch, Sumit G. Gandhi, Madhusudana Rao, Utpal Bhadra, James A. Birchler and Sarah C. R. Elgin, 2004. Heterochromatic silencing and HP1 localization in Drosophila are dependent on the RNAi machinery. Science 303: 669-672.
*Jin W, Lamb JC, Vega JM, Dawe RK, Birchler JA, Jiang J., 2005. Molecular and functional dissection of the maize B chromosome centromere. Plant Cell. May;17(5):1412-23.
*Han F, Lamb JC, Birchler JA., 2006 High frequency of centromere inactivation resulting in stable dicentric chromosomes of maize. Proc Natl Acad Sci U S A. 2006. Feb 28;103(9):3238-43.
Research Overview
Their longest standing research area has been how changes in chromosomal dosage affect gene expression and the organism. The results indicate that most regulatory processes in multicellular eukaryotes have evolved to be expressed at a level and to operate in such a manner that they are rate limiting on phenotypic characteristics. This property of regulatory mechanisms has implications for a number of genetic phenomena as described below.
Both positive and negative dosage effects operate, although the latter are in the majority. One dose of a chromosome arm often increases target gene expression throughout the genome approximately two-fold relative to the normal diploid. The corresponding three doses can reduce gene expression to a lower limit of two thirds. If such modulation is produced by a chromosomal arm and it has an effect on a target gene varied on the same segment, the change in structural gene dosage is cancelled by this “inverse dosage effect” and dosage compensation results.
They are interested in how dosage dependent regulatory genes control the process of X chromosomal dosage compensation in Drosophila. Their recent work suggests that as the heteromorphic sex chromosomes have evolved, a redistribution of a histone acetylase has occurred to modify how the regulatory dosage effects of the single X in males alter target gene expression. The acetylase is sequestered from the autosomes to prevent the increased expression expected from the prevalence of negatively acting dosage regulators. When the complex is genetically destroyed, the acetylase returns to the autosomes and gene expression increases.
They have also found that hybrid vigor (heterosis) is apparently controlled by dosage dependent regulatory genes. Triploid inbreds and hybrids were produced and compared to diploid inbreds and hybrids. In the triploid situation, there are two types of hybrids (AAB and ABB). When measures of hybrid vigor were applied, the two types differed, indicating an influence of allelic dosage. Preliminary tests of gene expression of randomly selected genes show that hybrids exhibit increased or decreased gene expression per cell. The results have led us to the model that heterosis is a reflection of the fact that most regulatory processes are dosage dependent and that the vast majority of these genes act negatively. If they work less efficiently in hybrids, most target gene expression would be increased.
The lab also studies dispersed transgene silencing (cosuppression) in Drosophila. One type involves a transcriptional process in which the silenced transgenes are associated with the Polycomb group of repressive chromatin proteins. The second involves a posttranscriptional RNA turnover mechanism that possesses the molecular hallmarks characteristic of RNA interference. These mechanisms most likely exist as a genomic defense against transposon mobility and as a cellular shield against viruses. Recent studies in our lab have demonstrated that RNAi machinery is needed for Polycomb dependent transcriptional silencing as well as for proper heterochromatin formation.
Several years ago the laboratory cloned a repeat associated with the maize supernumerary chromosome centromere. Critical regions of this centromere have been defined that permit high fidelity of meiotic transmission. Current studies are involved with understanding the structure of the centromere repeats and their evolution. Also, we are in the process of using these fragments to attempt construction of maize artificial chromosomes, for which we are developing a wide variety of vectors and approaches. As an alternative, we have generated numerous minichromosomes containing little more than the centromere of the supernumerary chromosome, which could be purified and used in constructing yet a different type of vector. The eventual development of artificial chromosome technology will permit the directed study of the components needed for chromosomal behavior as well as many industrial applications. The ability to introduce complete biochemical pathways might confer new properties to the target plant or allow plants to be used as biological factories for the economical production of a desired end-product.
Lab Members - Current and Past
* James Birchler - Principal investigator
*Don Auger - Postdoctoral researcher
*Matthew Bauer - Graduate Student
*Utpal Bhadra - Postdoctoral researcher
*Manika Pal Bhadra - Postdoctoral researcher
*Jenny Cooper - Graduate Student
*Doug Davis
*Tatiana Danilova - Postdoctoral researcher
*Christopher Della Vedova - Graduate Student
*Mei Guo - Postdoctoral researcher
*Akio Kato - Postdoctoral researcher
*Etienne Kaszas
*Harsh Kavi - Graduate Student
*Jonathan Lamb - Graduate Student
*Rick Masonbrink - Graduate Student
*Peggy Northup - Lab Technician
*Tara Phelps-Dur - Graduate Student
*Brent Page - Graduate Student
*James Theuri - Postdoctoral researcher
Publications
For a list of current published research articles, please click on [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?dbpubmed&cmdSearch&itoolpubmed_AbstractPlus&term%22Birchler+JA%22%5BAuthor%5D here]
*Leonard Rabinow and James A. Birchler, 1989. A dosage sensitive modifier of retrotransposon induced alleles of the white locus of Drosophila. The EMBO Journal 8: 879-890.
*James A. Birchler, John C. Hiebert and Leonard J. Rabinow, 1989. Interaction of the mottler of white with transposable element alleles at the white locus in Drosophila melanogaster. Genes and Development 3: 73-84.
*Mei Guo and James A. Birchler, 1994. Trans-acting dosage effects on the expression of model gene systems in maize aneuploids. Science 266: 1999-2002.
*Mei Guo, Doug Davis and James A. Birchler, 1996. Dosage effects on gene expression in a maize ploidy series. Genetics 142: 1349-1355.
*James A. Birchler, 1996. X chromosome dosage compensation in Drosophila. Science 272: 1190.
*Etienne Kaszas and James A. Birchler, 1996. Misdivision analysis of centromere structure in maize. EMBO Journal 15: 5246-5255.
*Manika Pal-Bhadra, Utpal Bhadra and James A. Birchler, 1997. Cosuppression in Drosophila: gene silencing of Alcohol dehydrogenase by white-Adh transgenes is Polycomb dependent. Cell 90: 479-490.
*Manika Pal Bhadra, Utpal Bhadra and James A. Birchler, 1999. Cosuppression of non-homologous transgenes in Drosophila involves mutually related endogenous sequences. Cell 99: 35-46.
*Brent T. Page, Michael K. Wanous and James A. Birchler, 2001. Characterization of a maize chromosome 4 centromeric sequence: evidence for an evolutionary relationship with the B chromosome centromere. Genetics 159: 291-302.
*Manika Pal Bhadra, Utpal Bhadra and James A. Birchler, 2002. RNAi related mechanisms affect both transcriptional and post-transcriptional transgene silencing in Drosophila. Molecular Cell 9: 315-327.
*Cathy X. Zhong, Joshua B. Marshall, Christopher Topp, Rebecca Mroczek, Akio Kato, Kiyotaka Nagaki, James A. Birchler, Jiming Jiang and R. Kelly Dawe, 2002. Centromeric retroelements and satellites interact with maize kinetochore protein CENH3. The Plant Cell 14: 2825-2836.
*Manika Pal Bhadra, Boris A Leibovitch, Sumit G. Gandhi, Madhusudana Rao, Utpal Bhadra, James A. Birchler and Sarah C. R. Elgin, 2004. Heterochromatic silencing and HP1 localization in Drosophila are dependent on the RNAi machinery. Science 303: 669-672.
*Jin W, Lamb JC, Vega JM, Dawe RK, Birchler JA, Jiang J., 2005. Molecular and functional dissection of the maize B chromosome centromere. Plant Cell. May;17(5):1412-23.
*Han F, Lamb JC, Birchler JA., 2006 High frequency of centromere inactivation resulting in stable dicentric chromosomes of maize. Proc Natl Acad Sci U S A. 2006. Feb 28;103(9):3238-43.