Traditional models of inheritance identify genetic material as being the only medium by which information can be transferred from parent to progeny. However, increasing evidence suggests that epigenetically encoded signals - information not directly encoded by the DNA sequence - can also be passed down to offspring in a phenomenon known as transgenerational epigenetic inheritance, or TEI. To study this phenomenon, we use the nematode Caenorhabditis elegans as our model organism.
Within C. elegans, perinuclear RNP condensates found in the germline – termed ‘germ granules’ – have been identified as being crucial for regulating gene expression, as well as the inheritance of small non-coding RNA epigenetic signals. It has been suggested that these granules act as processing ‘hubs’, bringing small RNA molecules, proteins, and mRNA transcripts together spatiotemporally to coordinate appropriate gene regulation and silencing responses. Indeed, disruption of germ granules has been shown to result in heritable aberrant gene silencing, a mortal germline phenotype ultimately resulting in sterility, and defective TEI. It is clear that proper formation of these condensates is needed for controlled epigenetic signaling, both within the individual and transgenerationally.
As many genes involved in TEI localize to the germ granules, we are interested in investigating the interplay between their products and the formation of granules, and whether TEI-defective mutants disrupt this. We have identified genes of interest that we wish to more fully elucidate the role of, and introduced their mutants into a worm strain with fluorescently-tagged germ granule proteins, allowing us to visualize their structure by proxy. The resulting high-resolution fluorescent microscopy images will be presented, alongside image analysis outlining any structural changes or otherwise that have been observed.