FGF Is an Essential Regulator of the Fifth Cell Division in Preimplantation Mouse Embryos

摘要: Fibroblast growth factor (FGF) signaling is required prior to gastrulation in the mouse embryo. To test for spatial and temporal requirements of FGF signaling, a dominant negative receptor (dnFGFR) was used make transgenic embryos. In mosaic embryos, cell division ceased at fifth all cells that expressed mutant receptor, but death did not increase. After division, progeny unaltered expressing lacZ continued accumulate same rate, suggesting requirement autonomous. lacZ, dnFGFR expression detected mitotic trophoblasts adjacent ICM. Conversely, dnFGFR-expressing extraembryonic ectoderm were abembryonic pole postmitotic cells. blastocysts cells, morphology appeared normal inner masses (ICMs) formed, resultant embryos had only one-third number as control these blastocysts, also cavitation, concurrent morphogenetic event, initiated progressed normally. continuing FGF, FGFR-3 overexpressed resulted an increase numbers after cycle. model postimplantation development, addition FGF-4 blastocyst outgrowths increased role FGF. Thus, induces embryonic preimplantation embryo starting division. The signal autonomous, prevent death. This provides first evidence necessity before implantation.