Microarray analysis of gene expression profiles in Map2k1+/-Map2k2+/- and Map2k1flox/-Map2k2+/-Tg+/Sox2Cre placentas

The mammalian genome contains two ERK/MAP kinase kinase genes, Map2k1 and Map2k2, encoding dual-specificity kinases responsible for ERK/MAP kinase activation. Loss of Map2k1 function in mouse causes embryonic lethality due to placental defects, while Map2k2 mutant mice survive with a normal lifespan. The Map2k1 mutation interferes with the growth of the labyrinthine region of the placenta and its vascularization. Map2k1+/-Map2k2+/- embryos also die during gestation of underdevelopment of the labyrinth. In Map2k1+/-Map2k2+/- mutants, the vascularization of the labyrinth is reduced and defects in SynT-II formation lead to the accumulation of multinucleated trophoblasts giant cells (MTG). Deletion of both Map2k1 alleles in allantoïs-derived tissues in Map2k1+/ Map2k2+/- placenta (Map2k1flox/-Map2k2+/-Tg+/Sox2Cre) increases the penetrance and the expressivity of the MTG placental phenotype. Microarray analysis with RNA extracted from placentas of E12.5 wt, Map2k1+/-Map2k2+/- and Map2k1flox/-Map2k2+/-Tg+/Sox2Cre embryos was performed to evaluate the molecular impact of the loss of Map2k alleles on placenta development. Total RNA was isolated from placentas of E12.5 Map2k1+/+Map2k2+/+(control), from E12.5 Map2k1+/-Map2k2+/- embryos (experimental) and from E12.5 and Map2k1flox/-Map2k2+/-Tg+/Sox2Cre embryos (experimental). Four specimens were analyzed per genotype.