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bioRxiv · 10.1101/2021.10.03.462952

A sensitized genetic screen to identify regulators of C. elegans germline stem cells

Robinson-Thiewes, S.·Kershner, A. M.·Shin, H.·Haupt, K. A.·Kroll-Conner, P.·Kimble, J.
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Abstract

Germline stem cells (GSCs) in Caenorhabditis elegans are maintained by GLP-1/Notch signaling from the niche and by a downstream RNA regulatory network. Loss of the GLP-1 receptor causes GSCs to precociously undergo meiotic differentiation, the "Glp" phenotype, due to a failure to self-renew. lst-1 and sygl-1 are functionally redundant direct targets of GLP-1 signaling whose gene products work with PUF RNA binding proteins to promote GSC self-renewal. Whereas single loss-of-function mutants are fertile, lst-1 sygl-1 double mutants are sterile and Glp. We set out to identify genes that function redundantly with either lst-1 or sygl-1 to maintain GSCs. To this end, we conducted forward genetic screens for Glp mutants in genetic backgrounds lacking functional copies of either lst-1 or sygl-1. The screens generated nine glp-1 alleles, two lst-1 alleles, and one allele of pole-1, which encodes the catalytic subunit of DNA polymerase {varepsilon}. Three glp-1 alleles reside in Ankyrin (ANK) repeats not previously mutated. pole-1 single mutants have a low penetrance Glp that is enhanced by loss of either lst-1 or sygl-1. Thus, the screen uncovered one locus that interacts genetically with both lst-1 and sygl-1 and generated useful mutations for further studies of GSC regulation.

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Robinson-Thiewes, S., Kershner, A. M., Shin, H., Haupt, K. A., Kroll-Conner, P., Kimble, J.. 2021-10-05. A sensitized genetic screen to identify regulators of C. elegans germline stem cells. https://doi.org/10.1101/2021.10.03.462952

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