RUNX regulates the structure and function of the vulva in Caenorhabditis elegans

Abstract

RUNXs(Runt-related transcription factors), one of the important transcription factors family, is known to be involved in animal development and tumorogenesis. RUNX1 is a conserved transcription factor that regulates differentiation and development in multicellular organelles. rnt-1 encodes the sole C. elegans homolog of the Runx family of transcription factors, and is required for several developmental processes such as hypodermal seam cell proliferation and male tail development. However, detailed molecular genetic pathways involved in rnt-1 pathway are largely unknown. In this study, we found rnt-1 loss-of-function mutants show abnormal vulva, including protruding vulva (Pvl) and ruptured vulva (Rv) in C. elegans. To determine whether abnormal vulva formation was caused by rnt-1 gene deficiency, we observed abnormal vulva formation after day 1 adult worms. In this experiment, we used two types of rnt-1 deletion mutant allele including rnt-1(ok351) and rnt-1(tm388), both of which identified abnormal vulva formation.

We have identified phenotypes related to the vulva and reproductive organs of C. elegans to find out why the vulva develops abnormally in rnt-1 mutant animals. Through this experiment, it was confirmed that the number of eggs produced by the rnt-1 mutant animals were reduced compared to the wild type animals, and the number of eggs contained in the uterus was also reduced. In addition, observing the serotonin-mediated egg laying phenotype, it was confirmed that egg laying was promoted at low concentrations of serotonin treatment, but egg laying was inhibited as high concentration of serotonin was treated. In order to determine when abnormal vulva formation occurs from the developmental stage, we confirmed the vulvar progenitor cell formation process of young larvae mutant animals by differential interference contrast microscopy. The shape and arrangement of the worms appear to be uneven and irregular compared to the wild type animals.

Through these results, it was confirmed that not only the structure of the vulva but also the reproductive function of the rnt-1 mutant C. elegans, which is thought to be caused by abnormal morphology and arrangement of the vulva progenitor cells in the larval stage.