Bcl-x splicing regulatory machinery

The Bcl-x splicing regulatory machinery is a multi-component system responsible for the alternative splicing of the BCL2L1 gene, which produces two isoforms with antagonistic roles in programmed cell death (PubMed ID: 8348611). The long isoform, Bcl-xL, is a potent anti-apoptotic protein often overexpressed in various cancers, while the short isoform, Bcl-xS, promotes apoptosis by antagonizing Bcl-2 and Bcl-xL. This regulatory machinery includes various trans-acting RNA-binding proteins such as Sam68 (KHDRBS1), hnRNP F/H, RBM25, and SR proteins, which interact with cis-regulatory elements within the BCL2L1 pre-mRNA (PubMed ID: 17332752, 18364396). In oncogenic contexts, these factors are often dysregulated to favor the production of Bcl-xL, contributing to tumor progression and chemoresistance. Therapeutic interventions, such as splice-switching oligonucleotides (SSOs) and small-molecule splicing modulators, are designed to redirect the splicing process toward the pro-apoptotic Bcl-xS isoform (PubMed ID: 11502715). While promising for cancer therapy, targeting this machinery faces challenges such as achieving tissue specificity and avoiding dose-limiting thrombocytopenia, as Bcl-xL is essential for platelet longevity (PubMed ID: 17379805).

Other names

BCL2L1 splicing complexBcl-x alternative splicing machineryBcl-x spliceosome regulatory complex

Modulation of alternative splicing to shift the ratio from anti-apoptotic Bcl-xL to pro-apoptotic Bcl-xS isoforms by sterically blocking splice sites or inhibiting regulatory kinases.