Mutation of GLP-1/Notch RAM domain results in a strong Glp-1 phenotype

The distal tip cell niche uses GLP-1 /Notch signaling to maintain <i>C. elegans</i> germline stem cells. The RAM domain, which resides within the intracellular portion of the GLP-1 /Notch receptor, is integral to formation of a signaling-dependent transcription activation complex. Here we report the generation of a mutation in the GLP-1 RAM domain, created in a GLP-1 /Notch receptor with a C-terminal V5 tag. The phenotype of <i>glp-1 (RAM ^mut ) ^V5</i> homozygotes is similar to that of <i>glp-1</i> null mutants, but expression of the GLP-1 (RAM ^mut ) ^V5 protein was normal in the <i>glp-1 (RAM ^mut ) ^V5 </i> heterozygotes. We conclude that the RAM mutation abolishes receptor activity.