Very early in embryogenesis, germ cells, the cells that give rise to egg and sperm, are set aside from the somatic cells which give rise to the rest of the cells in our bodies. While germ cells are not necessary for survival of the individual, they are crucial for survival of the species. In her first talk, Dr. Ruth Lehmann explains that there are two mechanisms by which germ cells are specified in the early embryo; via germ plasm or via induction. Germ cells specified via either mechanism have in common the presence of germ granules; large, membraneless, ribo-nuclear particles. Interestingly, certain families of RNA regulatory proteins are conserved in germ granules across species. Lehmann describes work from her lab and others on the life cycle of germ granules in Drosophila, including how they are assembled, their interesting biophysical properties and how proteins and RNAs are organized within the granules.
In her second talk, Lehmann focuses on the establishment of the dichotomy between somatic and germ line fate. She explains how Drosophila germ cells develop to become so different from the somatic cells that make up the rest of the embryo. Germ cell development depends solely on maternal transcripts from the egg, while development of the soma depends on new zygotic transcription. Lehmann describes how two different molecular strategies, precise spatially controlled protein degradation and complete interference with the mRNA transcriptional elongation process, are employed to prevent somatic differentiation, thus allowing germ cell specific gene expression to occur.
Ruth Lehmann is the Laura and Isaac Perlmutter Professor of Cell Biology, Chair of the Department of Cell Biology, and Director of the Skirball Institute of Biomolecular Medicine at the New York University School of Medicine. She is also an Investigator of the Howard Hughes Medical Institute. Lehmann received her PhD from the University… Continue Reading