UC San Diego

Proper regulation of microtubule dynamics is critical for multiple events in embryogenesis, as microtubules are key cellular components that contribute to cell division, polarity, and migration. In C. elegans, the precise involvement and regulation of microtubules during embryonic development remains unclear. Our lab previously identified a gain-of-function (gf) mutation in an alpha-tubulin tba-1, which causes embryonic lethality at the restrictive temperature of 25°C. To identify the interactors of TBA-1 during embryo development, an EMS mutagenesis screen was performed and several lines that show suppression of tba-1(gf) embryonic lethality at 25°C were isolated. In this thesis, I analyzed the WGS data for all the obtained tba-1(gf) suppressor lines and focused on mapping the causative mutation for the ju1911 suppressor allele. By generating ju1911 recombinants, the genetic position of ju1911 is narrowed down to between -2.95 and +5.3 on chromosome III, containing function-altering mutations in two genes. I checked the candidate gene mapk-15 by introducing a loss-of-function allele in the tba-1(gf) background and CRISPR-Cas9 mediated gene knockout. I found that mapk-15(III, -1.42) is not responsible for the suppression. Overall, this study shows the disruptive effect of TBA-1(gf) in embryo development and narrows down the genetic locus of one of the tba-1(gf) suppressor alleles.