SEL-8, a nuclear protein required for LIN-12 and GLP-1 signaling in Caenorhabditis elegans

LIN-12 and GLP-1 are members of the LIN-12/Notch family of receptors that m ediate cell-cell interactions during development. The sel-8 gene had been i dentified previously in a screen for suppressors of a mutation that constit utively activates LIN-12. Here, we report that sel-8 is essential for lin-1 2- and glp-1-mediated signaling, and that SEL-8 is a glutamine-rich nuclear protein. We postulate that SEL-8 serves as a transcriptional coactivator o r as an assembly factor for transcription complexes that contain the LIN-12 or GLP-1 intracellular domains.