This gene encodes the small subunit of DRB (5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole) sensitivity-inducing factor (DSIF) complex, which regulates mRNA processing and transcription elongation by RNA polymerase II. The encoded protein is localized to the nucleus and interacts with the large subunit (SUPT5H) to form the DSIF complex. Related pseudogenes have been identified on chromosomes 2 and 12. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Nov 2012]
Function:
Component of the DRB sensitivity-inducing factor complex (DSIF complex), which regulates mRNA processing and transcription elongation by RNA polymerase II. DSIF positively regulates mRNA capping by stimulating the mRNA guanylyltransferase activity of RNGTT/CAP1A. DSIF also acts cooperatively with the negative elongation factor complex (NELF complex) to enhance transcriptional pausing at sites proximal to the promoter. Transcriptional pausing may facilitate the assembly of an elongation competent RNA polymerase II complex. DSIF and NELF promote pausing by inhibition of the transcription elongation factor TFIIS/S-II. TFIIS/S-II binds to RNA polymerase II at transcription pause sites and stimulates the weak intrinsic nuclease activity of the enzyme. Cleavage of blocked transcripts by RNA polymerase II promotes the resumption of transcription from the new 3' terminus and may allow repeated attempts at transcription through natural pause sites. DSIF can also positively regulate transcriptional elongation and is required for the efficient activation of transcriptional elongation by the HISLV1 nuclear transcriptional activator, Tat. DSIF acts to suppress transcriptional pausing in transcripts derived from the HISLV1 LTR and blocks premature release of HISLV1 transcripts at terminator sequences.
Subcellular Location:
Nucleus.
Tissue Specificity:
Widely expressed.
Similarity:
Belongs to the SPT4 family.
SWISS:
P63272
Gene ID:
6827
Database links:
Entrez Gene: 6827 Human
Entrez Gene: 20922 Mouse
Entrez Gene: 287608 Rat
Entrez Gene: 436782 Zebrafish
Omim: 603555 Human
SwissProt: P63272 Human
SwissProt: P63271 Mouse
SwissProt: B5DEM7 Rat
SwissProt: Q6DGQ0 Zebrafish
Unigene: 439481 Human
Unigene: 622 Mouse
Unigene: 7906 Rat
Unigene: 79365 Zebrafish
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