Alternative titles; symbolsSF3A, 120-KD SUBUNIT; SF3A120SPLICEOSOME-ASSOCIATED PROTEIN, 114-KD; SAP114PRP21, S. CEREVISIAE, HOMOLOG OF; PRP21HGNC Approved Gene S...
Alternative titles; symbols
HGNC Approved Gene Symbol: SF3A1
Cytogenetic location: 22q12.2 Genomic coordinates (GRCh38): 22:30,331,987-30,356,893 (from NCBI)
Introns are removed from nuclear pre-mRNA in 2 transesterification reactions. Splicing takes place in a large ribonucleoprotein particle, the spliceosome. Spliceosomal intermediate complexes form on pre-mRNA in the order E, A, B, and C, with the catalytic reactions occurring in complex C. U2 small nuclear ribonucleoproteins (snRNPs; see 180690) are among the proteins essential for spliceosome assembly and mRNA splicing. Functional U2 snRNP is composed of a 12S unit and 2 splicing factors, SF3A, which is composed of 3 proteins, including SF3A1, and SF3B, which is composed of 4 proteins (see SF3B1; 605590) (summary by Kramer et al. (1995), Wang et al. (1998), and Isono et al. (2001)).
▼ Cloning and Expression
By PCR using degenerate primers corresponding to micropeptide sequences of the SF3A 120-kD subunit, followed by screening a HeLa cell cDNA library, Kramer et al. (1995) isolated a cDNA encoding SF3A1, which they termed SF3A120. Sequence analysis predicted that the 793-amino acid protein is rich in prolines and charged amino acids. SF3A1 contains 2 SURP modules (see SFRS8; 601945) close to its N terminus and a ubiquitin (191339)-like region in its C terminus. Northern blot analysis revealed ubiquitous expression of 3.2-, 3.8-, and 5.7-kb transcripts, with the 5.7-kb transcript expressed less abundantly than the other two. Western blot analysis showed expression of a 120-kD protein from reticulocyte lysates or from HeLa cells.
▼ Gene Function
By binding analysis with truncated derivatives of SF3A1, Kramer et al. (1995) determined that SF3A1 interacts with SF3A3 (605596) through its SURP domain but with SF3A2 (600796) primarily through a 130-amino acid region C terminal to the SURP module.
By somatic cell hybrid analysis, Kramer et al. (1995) mapped the SF3A1 gene to chromosome 22.