Based on limited published evidence, BCLAF3 is a spliceosome component important for maintaining embryonic stem cell fate. It possesses DNA binding and transcription coregulator activity through mediator complex and RNA polymerase II-dependent mechanisms. BCLAF3 negatively regulates Wnt-driven stem cell renewal in gastric epithelial tissues by suppressing regenerating islet-derived (Reg) genes through regulation of epithelial interleukins 1. BCLAF3 knockout promotes Wnt-independent self-renewal of gastric epithelial cells, suggesting a role in promoting differentiation.