Ectopic expression of Cvh (Chicken Vasa homologue) mediates the reprogramming of chicken embryonic stem cells to a germ cell fate

10 pages, 6 figures.-- PMID: 19324033 [PubMed].-- Printed version published Jun 1, 2009.-- Supporting information available at: http://dx.doi.org/10.1016/j.ydbio.2009.03.012

When they are derived from blastodermal cells of the pre-primitive streak in vitro, the pluripotency of Chicken Embryonic Stem Cells (cESC) can be controlled by the cPouV and Nanog genes. These cESC can differentiate into derivatives of the three germ layers both in vitro and in vivo, but they only weakly colonize the gonads of host embryos. By contrast, non-cultured blastodermal cells and long-term cultured chicken primordial germ cells maintain full germline competence. This restriction in the germline potential of the cESC may result from either early germline determination in the donor embryos or it may occur as a result of in vitro culture. We are interested in understanding the genetic determinants of germline programming. The RNA binding protein Cvh (Chicken Vasa Homologue) is considered as one such determinant, although its role in germ cell physiology is still unclear. Here we show that the exogenous expression of Cvh, combined with appropriate culture conditions, induces cESC reprogramming towards a germ cell fate. Indeed, these cells express the Dazl, Tudor and Sycp3 germline markers, and they display improved germline colonization and adopt a germ cell fate when injected into recipient embryos. Thus, our results demonstrate that Vasa can drive ES cell differentiation towards the germ cell lineage, both in vitro and in vivo.

This work was supported by grants from INRA and the GenAnimal program (GenStem FNS-2004; ANR-06 GANI-007 Genostem) to B.P. and from the Spanish Ministry of Science and Innovation (BFU2008-01042/BMC and CONSOLIDER-INGENIO 2010 CSD2007-00017 and CSD2007-00023) to M.A.N.