Ruth Lehmann, PhD

In most organisms, primordial germ cells (PGCs) are set-aside early during embryogenesis. Subsequently, PGCs migrate through the embryo, associate with somatic gonadal cells and form the gonad. While PGCs seem highly specialized, their products are the ultimate stem cells that generate a complete organism generation after generation. Our long-term goal is to functionally dissect the germ cell life cycle in Drosophila. Projects in the lab focus on three areas. 1) PGC specification. Early Drosophila germ cells form in a specialized germplasm and upon formation are transcriptionally silent. We are interested how RNAs localized to germ plasm are regulated and contribute to germ cell formation and fate, how gene expression is regulated during germ cell development and how the reproductive success of individual PGCs is determined. 2) PGC migration. Taking advantage of in vitro migration assays and live imaging, we study molecular and cellular aspects of germ cell migration to understand how the migratory program is established, how phospholipid signals contribute guidance cues to PGCs and how PGCs cease migration once they reach the somatic gonad. 3) Germ cell genome protection. Germ cells give rise to a new generation, thus integrity of the germ cell genome has to be protected while at the same time there has to be room for improvement via mutation and recombination. We study how host mechanisms evolved to protect the genome against transposable elements and how other intruders such as bacteria influence germ line function and reproductive success.