Efficient TALEN-mediated gene targeting of chicken primordial germ cells.

In this work we use TALE nucleases (TALENs) to target a reporter construct to the () locus in chicken primordial germ cells (PGCs). Vasa is a key germ cell determinant in many animal species and is posited to control avian germ cell formation. We show that TALENs mediate homology-directed repair of the locus on the Z sex chromosome at high (8.1%) efficiencies. Large genetic deletions of 30 kb encompassing the entire locus were also created using a single TALEN pair. The targeted PGCs were germline competent and were used to produce null offspring. In knockout chickens, PGCs are initially formed but are lost during meiosis in the developing ovary, leading to adult female sterility. TALEN-mediated gene targeting in avian PGCs is therefore an efficient process.