BioProject

RNA-seq transcriptome analysis of C. elegans germlines that inherited only paternal chromosomes (non-Mendelian inheritance, 'red-head worms') and the germlines of their offspring ('offspring of red-head worms') vs. germlines that inherited both maternal and paternal chromosomes (Mendelian inheritance, HBR1280 control). Given that epigenetic marking of sperm chromosomes is faithfully transmitted through embryo cell divisions, and that sperm epigenetic marking is important in offspring, we tested if sperm epigenetic marking alone is sufficient for proper development of the germline in offspring. We utilized a mutant that, during the first embryonic division, delivers the sperm genome to the daughter cell that generates the germline and the oocyte genome to the other daughter cell (Besseling & Bringmann, 2016). This mutant over-expresses GPR-1, a protein involved in regulation of kinetochore pulling forces. GPR-1 over-expression results in excessive pulling forces, causing the paternal and maternal pronuclei to inappropriately move to opposite poles of the 1-cell embryo instead of merging in the center of the embryo. In this mutant background, ~60% of offspring undergo atypical chromosome segregation, generating mosaic embryos whose germlines are derived entirely from sperm chromosomes (Besseling & Bringmann, 2016). To track the parental genomes, differentially tagged histone transgenes were used: a GFP-tagged histone H2B encoded in the sperm genome, and a TdTomato-tagged histone H2B encoded in the oocyte genome. The mosaic embryos whose germline inherited only sperm chromosomes (‘red-head' worms) develop into fertile adults with a normal brood size, similar to control worms, in which the germline inherited both sperm and oocyte chromosomes. RNA-seq analysis demonstrated that the germline transcriptome of ‘red-head’ worms and their offspring show few (<80 genes) and minor changes compared to control worms. These findings demonstrate that epigenetic information provided by sperm can guide proper germ cell development. Overall design: Germlines from 'red-head' worms (2 replicates), germlines from offspring of 'red-head' worms (2 replicates) vs. control germlines from HBR1280 (2 replicates)