Reprogramming of early embryonic blastomeres into endodermal progenitors by a Caenorhabditis elegans GATA factor

The END-1 GATA factor has been implicated in specifying endoderm in Caenorh abditis elegans and is the earliest known zygotic protein expressed in the lineage of E, the clonal endoderm progenitor. We report that ubiquitous end -1 expression during a critical period in embryogenesis causes all non-endo dermal lineages to produce endoderm instead of ectoderm and/or mesoderm. EN D-1 expression bypasses the requirement for maternal SKN-1 and the maternal Wnt signaling pathway in endoderm formation. This suggests that a primary function of these maternal factors is to regulate zygotic end-1 expression, which is then sufficient to initiate the entire program for endoderm devel opment.