SRSF1 IS AN RNA-BINDING PROTEIN THAT FUNCTIONS AS A TRANSCRIPTIONAL ACTIVATOR

Serine/Arginine splicing factor 1 (SRSF1) is an RNA-binding protein (RBP) with multiple functions in RNA biogenesis. SRSF1 plays a prominent role in oncogenesis, immune function, and response to several physiological stimuli. To date, the role of SRSF1 as a regulator of mRNA splicing has been largely considered the main mechanism driving its biological functions and its role in disease. We have now characterized SRSF1’s role in Human Immunodeficiency Virus Type I (HIV-1) transcription. SRSF1 interacts with the 7SK small nuclear ribonucleoprotein (snRNP) to mobilize and activate the positive transcription-elongation factor (P-TEFb), which is then positioned on the HIV-1 promoter to increase the processivity of RNA polymerase II (RNAPolII) and promote the release of the negative regulators of transcription DSIF/NELF. Next, we defined the role of SRSF1 in the transcription of cellular genes utilizing an RNA sequencing (RNASeq) time course approach was used to detect changes in the transcriptome in response to SRSF1 overexpression. RNASeq data analysis revealed a subset of genes that were upregulated in response to SRSF1 overexpression. Nuclear run-on and qPCR assays experimentally validated 28 of these genes.