Splicing factor 3B complex (SF3b complex) (SF3b)

Splicing factor 3B complex (SF3b) is a multi-protein complex that forms a core part of the U2 small nuclear ribonucleoprotein (U2 snRNP) component of the spliceosome, the molecular machinery responsible for precursor mRNA (pre-mRNA) splicing in eukaryotes[1][2][3]. SF3b recognizes the branch point adenosine within introns and anchors the U2 snRNP to pre-mRNA during splicing. The complex includes seven subunits (notably SF3B1, SF3B3, SF3B4, among others), each with specific structural and functional roles. Recent studies have demonstrated additional functions of SF3b subunits, such as the involvement of SF3b4 in translational control and mRNA export beyond canonical splicing activity[3][4]. Somatic mutations, especially in the SF3B1 gene, are strongly associated with certain myelodysplastic syndromes and cancers. SF3b is an emerging therapeutic target, with several drugs in development that modulate its role in splice site selection and splicing fidelity[2][3][4].

Other names

Splicing factor 3BSF3B complexSF3B1 (when referring to the main subunit)U2 snRNP-associated splicing factor 3b

Modulation of spliceosome function Inducing or correcting aberrant splicing patterns Alteration of branch point recognition