DSIF

In gene expression, DSIF (DRB Sensitivity Inducing Factor) is a protein that can either negatively or positively affect transcription by RNA polymerase II (Pol II). In one case of negative regulation, it can interact with negative elongation factor (NELF) to promote the stalling of Pol II at some genes. This stalling is relieved by P-TEFb. In humans, DSIF is composed of hSPT4 and hSPT5 (SPT4 and SPT5 are homologs in yeast).^[1]

References

1. Wenzel, Sabine; Schweimer, Kristian; Rösch, Paul; Wöhrl, Birgitta M. (June 2008). "The small hSpt4 subunit of the human transcription elongation factor DSIF is a Zn-finger protein with α/β type topology". Biochemical and Biophysical Research Communications 370 (3): 414–418. doi:10.1016/j.bbrc.2008.03.080. PMID 18373978. Retrieved 18 December 2014.