Distal promoter

A distal promoter is a portion of the promoter for a particular gene. This distal sequence upstream of the gene is a region of DNA that may contain additional regulatory elements, often with a weaker influence than the proximal promoter.
Promoter
In genetics, a 'promoter' is a region of DNA that facilitates the transcription of a particular gene. Promoters are located near the genes they regulate, on the same strand and typically upstream (towards the 5' region of the sense strand).
Proximal promoter
A 'proximal promoter' is a proximal sequence upstream of the gene, specifically the transcription start site (TSS) of the gene, that tends to contain primary regulatory elements. It is approximately 250 base pairs (bp) upstream (signified by a negative sign before the number of base pairs, eg. -250 bp) of the TSS and has specific transcription factor binding sites.
Glucocorticoid responsive element
A 'glucocorticoid responsive element' (GRE) acts as a hormonally regulated enhancer. GREs are located upstream from the transcription start site of the specific gene for enhanced (repetitive) transcription. Usually they are in pairs.
Two GREs are located some 2.5 kb upstream of the transcription initiation site of the tyrosine aminotransferase gene, for example. The proximal GRE has no inherent capacity by itself to stimulate transcription. The degenerate nucleotide 'N' is A/C/G/T, where A is adenine, C is cytosine, G is guanine, and T is thymine.
An E-box usually lies within the distal promoter starting at or near -300 bp, the proximal promoter, or both. The critical region for transcription activity is located within -27/-17 bp upstream from the TSS.<ref nameHasegawa/> In contrast to the proximal promoter, which is trans-activated by YY1 and PU.1, these transcription factors, including ELF1, exhibit repressive function on this promoter.<ref nameHasegawa/> Addition of IL-4 causes a marked increase in transcription from the distal promoter and subsequent increase in the intracellular production of the alpha chain.<ref nameHasegawa/> IL-4-dependent up-regulation of the human alpha chain is due to enhancement of distal promoter activity.<ref nameHasegawa/> The two promoters appear to have different regulatory mechanisms for alpha-chain expression.<ref name=Hasegawa/>
Other cis-regulatory elements may be present in the -221/-28 region; one may be the suppressing region (-221/-80), and the other may be the activating region (-79/-28).<ref name=Hasegawa/>

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