Exploring Centromeric Epigenetic Regulation in C. elegans (2016)

Undergraduates: Cole Barnhardt, Lydia Smith Ethan Hughes

Faculty Advisor: Paul Maddox
Department: Biology

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Centromeres are regions of chromosomes necessary for their segregation during cell division. Unlike genes in the genome, centromeres are not defined by their DNA sequence, but ¿¿¿epigenetically¿¿¿ by modifications and proteins localized at these regions. Previously we showed that there is a molecular switch that maintains the epigenetic mark of centromeres. Loss of this molecular switch results in a loss of the proteins responsible for establishing where centromeres are located on the chromosome and thus failure of chromosome segregation. We will elaborate this mechanism using the model organism Caenorhabditis elegans. C. elegans is a species of transparent roundworm that is commonly used to study complex biological events due to their simple physiology and available research tools. We are determining how the centromere molecular switch directly regulates the maintenance of the epigenetic marks of centromeres. We found that when we knocked down this molecular switch in C. elegans there was a defect in the maintenance of the centromeric proteins in the pronuclei stage of zygotes. This effect was observed in the oocyte nuclei but not in the sperm nuclei. Our results indicate that there are observable differences between oocyte and sperm pronuclei in regards to the aforementioned molecular switch. Our findings will impact how we understand chromosome segregation in cell division and likely lead to new therapeutic strategies in diseases such as cancer.