Cyclins E1 and E2 are required for endoreplication in placental trophoblast giant cells.

ABSTRACT: In mammalian cells, cyclin E-CDK2 complexes are activated in the late G1 phase of the cell cycle and are believed to have an essential role in promoting S-phase entry. We have targeted the murine genes CCNE1 and CCNE2, encoding cyclins E1 and E2. Whereas single knockout mice were viable, double knockout embryos died around midgestation. Strikingly, however, these embryos showed no overt defects in cell proliferation. Instead, we observed developmental phenotypes consistent with placental dysfunction. Mutant placentas had an overall normal structure, but the nuclei of trophoblast giant cells, which normally undergo endoreplication and reach elevated ploidies, showed a marked reduction in DNA content. We derived trophoblast stem cells from double knockout E3.5 blastocysts. These cells retain

SUBMITTER: Parisi T 

PROVIDER: S-EPMC212738 | biostudies-literature | 2003 Sep

REPOSITORIES: biostudies-literature