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Protein SF3B4 PDB 1x5t.png
Available structures
PDB Ortholog search: PDBe RCSB
Aliases SF3B4, AFD1, Hsh49, SAP49, SF3b49, splicing factor 3b subunit 4
External IDs MGI: 109580 HomoloGene: 134086 GeneCards: SF3B4
RNA expression pattern
PBB GE SF3B4 209044 x at fs.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 1: 149.92 – 149.93 Mb Chr 3: 96.17 – 96.18 Mb
PubMed search [1] [2]
View/Edit Human View/Edit Mouse

Splicing factor 3B subunit 4 is a protein that in humans is encoded by the SF3B4 gene.[3][4]


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.[4]

Disease associations[edit]

In 2012, Canadian researchers belonging to the FORGE (Finding of Rare disease GEnes) consortium identified new dominant mutations in SF3B4 as the cause of Nager syndrome, a rare type of mandibulofacial dysostosis with associated limb malformations.[5]


SF3B4 has been shown to interact with CDC5L,[6] BMPR1A[7] and SF3B2.[3][8]


  1. ^ "Human PubMed Reference:". 
  2. ^ "Mouse PubMed Reference:". 
  3. ^ a b Champion-Arnaud P, Reed R (Aug 1994). "The prespliceosome components SAP 49 and SAP 145 interact in a complex implicated in tethering U2 snRNP to the branch site". Genes & Development. 8 (16): 1974–83. doi:10.1101/gad.8.16.1974. PMID 7958871. 
  4. ^ a b "Entrez Gene: SF3B4 splicing factor 3b, subunit 4, 49kDa". 
  5. ^ Bernier FP, Caluseriu O, Ng S, Schwartzentruber J, Buckingham KJ, Innes AM, Jabs EW, Innis JW, Schuette JL, Gorski JL, Byers PH, Andelfinger G, Siu V, Lauzon J, Fernandez BA, McMillin M, Scott RH, Racher H, Majewski J, Nickerson DA, Shendure J, Bamshad MJ, Parboosingh JS (May 2012). "Haploinsufficiency of SF3B4, a component of the pre-mRNA spliceosomal complex, causes Nager syndrome". American Journal of Human Genetics. 90 (5): 925–33. doi:10.1016/j.ajhg.2012.04.004. PMID 22541558. 
  6. ^ Ajuh P, Kuster B, Panov K, Zomerdijk JC, Mann M, Lamond AI (Dec 2000). "Functional analysis of the human CDC5L complex and identification of its components by mass spectrometry". The EMBO Journal. 19 (23): 6569–81. doi:10.1093/emboj/19.23.6569. PMC 305846Freely accessible. PMID 11101529. 
  7. ^ Nishanian TG, Waldman T (Oct 2004). "Interaction of the BMPR-IA tumor suppressor with a developmentally relevant splicing factor". Biochemical and Biophysical Research Communications. 323 (1): 91–7. doi:10.1016/j.bbrc.2004.08.060. PMID 15351706. 
  8. ^ Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP, Vidal M (Oct 2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173–8. doi:10.1038/nature04209. PMID 16189514. 

Further reading[edit]

External links[edit]