SF3B1
Description
The SF3B1 (splicing factor 3b subunit 1) is a protein-coding gene located on chromosome 2.
SF3B1, also known as Splicing factor 3B subunit 1, is a protein encoded by the SF3B1 gene in humans. It forms part of the splicing factor 3b protein complex, which, along with splicing factor 3a and a 12S RNA unit, makes up the U2 small nuclear ribonucleoproteins complex (U2 snRNP). The splicing factor 3b/3a complex binds to pre-mRNA upstream of the intron's branch site and anchors the U2 snRNP to the pre-mRNA. SF3B1 is also involved in the minor U12-type spliceosome. Mutations in SF3B1 have been linked to advanced chronic lymphocytic leukemia, myelodysplastic syndromes, and breast cancer. They are particularly prevalent in patients with refractory anemia with ring sideroblasts (RARS) or RARS with thrombocytosis (RARS-T). Emerging evidence suggests a potential role of SF3B1 mutations in orbital melanoma.
SF3B1 is a component of the 17S U2 snRNP complex, a large ribonucleoprotein complex involved in removing introns from pre-mRNAs. The 17S U2 snRNP complex plays a key role in early spliceosome assembly and recognizes the intron branch site during pre-mRNA splicing by selecting the branch-site adenosine, which is crucial for the first splicing step. Within the complex, SF3B1 is part of the SF3B subcomplex, essential for forming the 'A' complex through stable binding of U2 snRNP to the branchpoint sequence in pre-mRNA. Binding of SF3A and SF3B subcomplexes upstream of the branch site is critical and may anchor U2 snRNP to the pre-mRNA. SF3B1 might also participate in assembling the 'E' complex. Additionally, it acts as a component of the minor spliceosome, which is involved in splicing U12-type introns in pre-mRNAs. Along with other U2 snRNP complex components, SF3B1 may play a role in the selective processing of microRNAs (miRNAs) from the long primary miRNA transcript, pri-miR-17-92.
SF3B1 is also known as Hsh155, MDS, PRP10, PRPF10, SAP155, SF3b155.
