HTATSF1
Description
The HTATSF1 (HIV-1 Tat specific factor 1) is a protein-coding gene located on chromosome X.
HTATSF1 is a protein that in humans is encoded by the HTATSF1 gene. It primarily functions in stimulating elongation and interacting with the TAR RNA element, which is crucial for HIV replication. HTATSF1 is also involved in intron retention and splicing of ribosomal protein mRNAs. It is linked to a naïve pluripotent state but its relationship is complex and influenced by other pluripotency factors. HTATSF1 interacts with SUPT5H and GTF2F2.
HTATSF1 is a component of the 17S U2 SnRNP complex, a key part of the spliceosome, which is responsible for removing introns from pre-mRNA transcripts. This complex plays a crucial role in early spliceosome assembly and recognizing the intron branch site, selecting the branch-site adenosine needed for the initial splicing step. HTATSF1 stabilizes the branchpoint-interacting stem loop within the complex. It is displaced before the 17S U2 SnRNP complex binds stably to the spliceosome, allowing for probing of intron branch site sequences. HTATSF1 also acts as a regulator of transcriptional elongation, possibly by linking splicing to transcriptional elongation. In addition, HTATSF1 contributes to double-strand break repair through homologous recombination during the S-phase of the cell cycle by recruiting TOPBP1 to DNA damage sites. It achieves this by interacting with poly-ADP-ribosylated RPA1 and being phosphorylated by CK2, facilitating RAD51 nucleofilament formation and RPA displacement, ultimately leading to homologous recombination.
HTATSF1 is also known as TAT-SF1, TATSF1, dJ196E23.2.
