Reprogramming towards a germline stem cell fate

项目总结

Project Summary Germline cellular immortality underlies the continuation of all sexually reproducing species. Recent work has identified frequent examples of interconversion between germline and somatic fates, suggesting plasticity, rather than a strict dichotomy, between germline and soma. In adults, production of male gametes is driven by germline stem cell (GSC) division. In my postdoctoral work, I propose to use the powerfully tractable system of the Drosophila melanogaster male germline to identify necessary factors of immortal germline fate. In addition to undergoing normal self-renewal and differentiation, GSCs can be generated through dedifferentiation of spermatogonia, and can be lost through both forced differentiation to germ cells and transdifferentiation to soma. First, using single-cell RNA sequencing on testes cells in which the germline is undergoing dedifferentiation, I will reconstruct lineage transitions to identify genes underlying GSC formation from a differentiated cell, including both germline cell- autonomous factors and non-autonomous signaling factors. I will validate these data using both in vivo expression characterization and assays of gene function. Next, I will describe the transcriptional changes necessary for transdifferentiation of GSCs to somatic cells, identifying the components that maintain germline identity. Finally, I will leverage discovery of factors involved in both a) the creation of GSCs from differentiating cells, and b) the loss of GSC identity that results in somatic cell formation, in order to develop a novel model for inducible somatic reprogramming to a germline fate. This work will significantly further our understanding of the factors that confer cellular immortality, and will aid in the development of therapies for diverse human diseases.