RNAi pathways repress reprogramming of C. elegans germ cells during heat stress

Repression of cellular reprogramming in germ cells is critical to maintaining cell fate and fertility. When germ cells mis-express somatic genes they can be directly converted into other cell types, resulting in loss of totipotency and reproductive potential. Here we show that RNAi pathways play a key role in maintaining germline gene expression and totipotency after heat stress. By examining transcriptional changes that occur in mut-16 mutants, that lack a key protein in the RNAi pathway, at elevated temperatures we found that soma-specific genes are mis-expressed in germ cells. This trend was also observed in hrde-1 mutants, which fail to direct transcriptional silencing of RNAi-targeted genes. These findings indicate that the RNAi pathway plays a key role in preventing aberrant expression of somatic genes in the germline during heat stress. This regulation likely occurs in part through the maintenance of germline chromatin by the nuclear RNAi pathway. 12 mRNA-seq libraries, 12 small RNA-seq, and 12 ATAC-seq libraries were generated and analyzed. Each genotype per condition were generated in triplicate.