SF3B1 Back

splicing factor 3b, subunit 1, 155kDa

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NCBI Description of SF3B1

This gene encodes subunit 1 of the splicing factor 3b protein complex. Splicing factor 3b, together with splicing factor 3a and a 12S RNA unit, forms the U2 small nuclear ribonucleoproteins complex (U2 snRNP). The splicing factor 3b/3a complex binds pre-mRNA upstream of the intron's branch site in a sequence independent manner and may anchor the U2 snRNP to the pre-mRNA. Splicing factor 3b is also a component of the minor U12-type spliceosome. The carboxy-terminal two-thirds of subunit 1 have 22 non-identical, tandem HEAT repeats that form rod-like, helical structures. Alternative splicing results in multiple transcript variants encoding different isoforms.

Community Annotation of SF3B1 Add / Edit SF3B1: Annotations

Added by Rachel Frieman


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Figure notes

• "Mouse over" a mutation to see details.
• Missense green saturation indicates evolutionary conservation of the mutated positions.
• Red hashes in protein strip are splice sites.
• Blue-white-red bars are log2 copy ratio distributions (–1 to +1) from Zack et al. (2013).


SF3B1 is highly significantly mutated in
Chronic lymphocytic leukemia
21 patients (13%)
combined cohort
102 patients (2%)
17 patients (1%)
SF3B1 is significantly mutated in
SF3B1 is near significance in

Click on a tumor type to see its full list of significant genes.

Data details

Mutation list for SF3B1