All multicellular organisms that reproduce sexually rely on eggs to support early life. A team of scientists led by Ludwig Cancer Research scientist Arshad Desai used the tiny roundworm C. elegans as a model to better understand how eggs enable embryonic development using only the materials already present in them.
Their study, published March 24 in Cell, shows how small RNAs—a type of genetic material—and helper proteins play a critical role in fine-tuning that process. The researchers report that small RNAs work together with CSR-1, one of a class of proteins known as Argonautes, to help create the perfect C. elegans egg. Desai and his colleagues at Ludwig San Diego and the University of California, San Diego, School of Medicine found that small RNAs direct CSR-1 to target messenger RNA, which CSR-1 then slices. Messenger RNA is an intermediary of gene expression—the transcript of a gene, which is read to make an encoded protein. By varying the number of small RNAs bound to a CSR-1 enzyme, eggs can precisely tune the composition of materials within them in order to support embryonic development. Their findings are of relevance to higher organisms as mice too use an Argonaute protein and small RNAs to control their egg composition.
A more detailed description of the study is available here.