PgmNr W4024: Investigating the remodeling of C. elegans primordial germ cells into germline stem cells.

Authors:
C. Maniscalco; J. Nance


Institutes
NYU School of Medicine, New York, NY.


Keyword: Germ line stem

Abstract:

Germ cells allow us to transmit our genome to future generations. The embryonic precursors of germ cells, called primordial germ cells (PGCs), are set aside early during development and are subjected to unique regulation, such as transcriptional repression, so that differentiation does not occur. In order to produce gametes, quiescent PGCs must activate and transition into dividing germline stem cells (GSCs). The mechanism of this transition, however, is poorly understood. The two embryonic PGCs in C. elegans extend large cytoplasm-filled lobes into the surrounding endoderm; lobes and their contents are subsequently removed and digested by endodermal cells (our unpublished observations), suggesting that they may function as a means for PGCs to discard unwanted components before they transition to GSCs. In support of this hypothesis, live imaging results show that PGC lobes concentrate certain cellular components, such as most of the mitochondria, before the lobes and their contents are pinched off and eaten by adjacent endodermal cells. In search of a mechanism for lobe formation, I observed that non-muscle myosin (NMY-2), a component of the contractile ring in dividing cells, forms a ring at the neck between PGCs and their lobes. This led us to hypothesize that lobes form when a contractile ring-like structure constricts the cell body into two halves. I am currently testing this hypothesis using temperature-sensitive mutations in components required for contractile ring function. By blocking formation of PGC lobes, I hope to determine if they function in the transition of PGCs to GSCs in the developing embryo.



Wormbase Genetic Index
1. nmy-2