Loss of function in rpms-1 does not enhance phenotypes of rpm-1 mutants

The E3 ubiquitin ligase RPM-1 consists of 3,766 amino acids, with a RING finger domain at the C-terminus that functions to target the DLK-1 kinase for degradation for synapse development and axon termination. for aka F07B7.12 resides 35 kb away from on chromosome V, and is a near-perfect 12 kb duplication of including the entire promoter region and coding sequences. RPMS-1 consists of 1,964 amino acids and is identical to the N-terminal half of RPM-1 , except the last 40 amino acids. Previous studies showed that transgenic overexpression of the duplicated region of did not rescue synapse defects of loss of function mutants. Here, using CRISPR editing, we generated a double knockout of and . We find that axon and synapse defects in double mutants resemble those in single mutants. Expression levels of endogenously tagged DLK-1 protein are increased to a comparable degree in and mutants, compared to the control. These data, along with previous transgene expression analysis, support the idea that does not have a major role in RPM-1-mediated cellular processes.