Splicing Factor 3B Subunit 4 (SF3B4)

SF3B4 cross-links to a region in the pre-mRNA immediately upstream of the branchpoint sequence in pre-mRNA in the prespliceosomal complex A. It also may be involved in the assembly of the B, C and E spliceosomal complexes. In addition to RNA-binding activity, this protein interacts directly and highly specifically with subunit 2 of the splicing factor 3B. This protein contains two N-terminal RNA-recognition motifs (RRMs), consistent with the observation that it binds directly to pre-mRNA.Sequence analysis predicted that the 424-amino acid protein contains 2 well-conserved RNA-recognition motifs (RRM) in its N terminus and that the remainder of the protein is highly proline and glycine rich. Northern blot analysis detected a 2.0-kb transcript in HeLa cells.