SF3B4 Antibody – Mouse Monoclonal

This gene encodes one of four subunits of the splicing factor 3B. The protein encoded by this gene 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. [provided by RefSeq, Jul 2008]

Function: Subunit of the splicing factor SF3B required for 'A' complex assembly formed by the stable binding of U2 snRNP to the branchpoint sequence (BPS) in pre-mRNA. Sequence independent binding of SF3A/SF3B complex upstream of the branch site is essential, it may anchor U2 snRNP to the pre-mRNA. May also be involved in the assembly of the 'E' complex. SF3B4 has been found in complex 'B' and 'C' as well. Belongs also to the minor U12-dependent spliceosome, which is involved in the splicing of rare class of nuclear pre-mRNA intron.

Subunit structure: Component of splicing factor SF3B which is composed of at least eight subunits; SF3B1/SAP155/SF3B155, SF3B2/SAP145/SF3B145, SF3B3/SAP130/SF3B130, SF3B4/SAP49/SF3B49, SF3B14A, PHF5A/SF3B14B, SF3B10 and SF3B125. SF3B associates with the splicing factor SF3A and a 12S RNA unit to form the U2 small nuclear ribonucleoproteins complex (U2 snRNP). Component of the U11/U12 snRNPs that are part of the U12-type spliceosome. SF3B4 interacts directly with SF3B2. Ref.7 Ref.8 Ref.9

Subcellular location: Nucleus

By similarity.

Involvement in disease: Acrofacial dysostosis 1, Nager type (AFD1) [MIM:154400]: A form of acrofacial dysostosis, a group of disorders which are characterized by malformation of the craniofacial skeleton and the limbs. The major facial features of AFD1 include downslanted palpebral fissures, midface retrusion, and micrognathia, the latter of which often requires the placement of a tracheostomy in early childhood. Limb defects typically involve the anterior (radial) elements of the upper limbs and manifest as small or absent thumbs, triphalangeal thumbs, radial hyoplasia or aplasia, and radioulnar synostosis. Phocomelia of the upper limbs and, occasionally, lower-limb defects have also been reported.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.13

Sequence similarities: Belongs to the SF3B4 family.Contains 2 RRM (RNA recognition motif) domains.