Identifying Negative Regulators of Notch in C. elegans Vulval Patterning (2013)

Undergraduate: Jessica Parks

Faculty Advisor: David Reiner
Department: Chemistry

---

EGFR and Notch contribute to many cancers. In C. elegans vulval development LET-23/EGFR and LIN-12/Notch pattern six vulval precursor cells to assume 3°-3°-2°-1°-2°-3° fates. The lin-12(n379d) activating mutation confers at most two excess 2° cells. We screened progeny and grandprogeny of EMS-mutagenized n379d parents for three or more ectopic 2° cells, obtaining nine mutations from 5448 haploid genomes. We assessed phenotype in absence of n379d. All seven tested mutations were n379d-dependent. We are mapping mutations by PCR detection of 48 SNP-snips. We cross the mutant (N2 background) to a polymorphic strain (CB4856 background) and re-isolate the mutant phenotype. N2/CB4856 SNP-snip allele proportions should be consistent except near lin-12 and the mutation, where CB4856 SNPs should be excluded. re48, re49, re51, re53, re54, and re55 mapped to chromosomes V, IV, III, X, I, and I, respectively. re48 is consistent with the lin-12 enhancers sel-9 or sel-10. re51 may be another mutation in lin-12 or another Notch gene glp-1. No known mutations in the intervals on chromosomes I, IV, or X are expected to cause this phenotype, suggesting re49, re53, re54, and re55 may define novel genes. We are pooling recombinant DNA lines for whole genome sequencing to corroborate SNP mapping and identify candidate genes. We hope to find novel regulators of LIN-12/Notch signaling, perhaps proteins involved in the EGFR-Notch interplay.