TheC. elegansfemale state: Decoupling the transcriptomic effects of aging and sperm-status

Understanding genome and gene function in a whole organism requires us to fully comprehend the life cycle and the physiology of the organism in question. Although C. elegans is traditionally thought of as a hermaphrodite, XX animals exhaust their sperm and become endogenous females after 3days of egg-laying. Themolecular physiology of this state has not been as intensely studied as other parts of the life cycle, despite documented changes in behavior and metabolism that occur at this stage. To study the female state of C. elegans , we measured the transcriptomes of 1st day adult hermaphrodites; endogenous, 6th day adult females; and at the same time points, mutant fog-2(lf) worms that have a feminized germline phenotype. At these time points, we could separate the effects of biological aging from the transition into the female state. fog-2(lf) mutants partially phenocopy 6 day adult wild-type animals and exhibit fewer differentially expressed genes as they age throughout these 6 days. Therefore, fog-2 is epistatic to age as assessed by this transcriptomic phenotype, which indicates that both factors act on sperm status to mediate entry into the female state. These changes are enriched in transcription factors canonically associated with neuronal development and differentiation. Our data provide a high-quality picture of the changes that happen in global gene expression throughout the period of early aging in the worm.