Transcriptomic Description of an Endogenous Female State in C. elegans

Abstract

Understanding genome and gene function in a whole organism requires us to fully understand the life cycle and the physiology of the organism in question. Although it is traditionally though of as a hermaphrodite, C. elegans XX animals become (endogenous) females after 3 days of egg-laying. The molecular physiology of this state has not been studied as intensely as other parts of the life cycle, in spite of documented changes in behavior and metabolism that occur at this stage. To study the female state of C. elegans, we designed an experiment to measure the transcriptome of 1st day adult females, endogenous, 6th day adult females, as well as mutant feminized worms that never go through a hermaphrodite stage at these time points. Using this experimental design, we were able to measure the effects of biological aging from the transition into the female state. We find that spermless young adult animals partially phenocopy 6 day old wild-type animals that have depleted their sperm after egg-laying, and that spermless animals also exhibit fewer transcriptomic changes associated with aging throughout these 6 days. Our results indicate that sperm loss is responsible for some of the naturally occuring transcriptomic changes that occur during the life cycle of these animals. These changes involve a variety of factors, and they 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.