Braun, Caleb J., Swann, Sellers, Lake, Menesha, Kreitz, Naden, Strickland, Kayman, Kroetz, Mary B.
[
International Worm Meeting,
2017]
During embryogenesis, the C. elegans gonad originates as a primordium of cells consisting of two somatic gonadal cells that flank two germ line precursor cells. The gonadal primordium is morphologically identical in the two sexes. Midway through the first larval stage, the somatic gonadal cells divide and differentiate, and during the course of development they will ultimately form one of two dramatically different organs: either a single-armed testis in the male or two bilaterally symmetric ovotestes connected to a central uterus in the hermaphrodite. To help define genes responsible for promoting gonadal development, we identified transcripts enriched for expression in the developing somatic gonad compared to the whole animal using cell-specific RNA-seq (Kroetz and Zarkower, 2015). Additionally, transcripts that were expressed in a sex-biased manner in the gonad have also been identified. Sex-biased transcripts were defined as transcripts that were enriched in one sex of gonadal cells compared to the expression in the gonadal cells of the other sex. Of the more than 900 gonad-enriched transcripts, approximately 80 encode for proteins that are transcriptional regulators. Seventeen transcription factors are expressed in a male-biased manner, and nine transcription factors are expressed in a hermaphrodite-biased manner in the developing gonad. To better understand if and how these transcription factors are controlling expression of the gonad-enriched transcripts, we are characterizing the expression patterns of proteins whose transcripts show the strongest gonadal enrichment. We are using CRISPR-Cas to fuse GFP to the C-terminus of the endogenously expressed gonadal proteins. We then use loss-of-function mutations or RNAi against the sex-biased or gonad-enriched transcription factors to determine if the transcription factors are important for expression of the GFP-tagged genes. This work will better define the transcriptional networks controlling gonad development and give insights into how key genetic regulators promote sex-specific organogenesis.