Mash2 acts cell autonomously in mouse spongiotrophoblast development

M Tanaka, M Gertsenstein, J Rossant, A Nagy - Developmental biology, 1997 - Elsevier
M Tanaka, M Gertsenstein, J Rossant, A Nagy
Developmental biology, 1997Elsevier
TheMash2gene, which encodes a basic helix-loop-helix transcription factor, is one of the
mammalian homologues of theDrosophila achaete-scutegenes. It is strongly expressed in
diploid trophoblast cells of the postimplantation mouse embryo. Targeted mutagenesis
ofMash2revealed that loss of function results in embryonic lethality at midgestation, due to
placental failure associated with a lack of spongiotrophoblast and reduced labyrinthine
trophoblast layers. For the further study of Mash2 function in development of the trophoblast …
TheMash2gene, which encodes a basic helix-loop-helix transcription factor, is one of the mammalian homologues of theDrosophila achaete-scutegenes. It is strongly expressed in diploid trophoblast cells of the postimplantation mouse embryo. Targeted mutagenesis ofMash2revealed that loss of function results in embryonic lethality at midgestation, due to placental failure associated with a lack of spongiotrophoblast and reduced labyrinthine trophoblast layers. For the further study of Mash2 function in development of the trophoblast cell lineage, we have performed chimeric analysis combiningMash2mutant and wild-type embryos. We have addressed the question of whether the phenotype of theMash2mutant embryo, which affects all of the three trophoblast cell layers, is caused by a cell autonomous or non-autonomous defect and whether Mash2 is required in both spongiotrophoblast and labyrinthine trophoblast development. Our results showed no contribution ofMash2mutant cells to the spongiotrophoblast layer in chimeric placentae at 10.5 and 12.5 days postcoitum, suggesting that the product of theMash2gene is required cell autonomously during the development of the spongiotrophoblast. However, it seems that Mash2 is not required for development of labyrinthine trophoblast or giant cells, since high contributions ofMash2mutant cells were observed in those trophoblast cell layers in the chimeric placentae analyzed. We can therefore conclude that the primary and cell-autonomous function of Mash2 appears to be an involvement in the development of diploid trophoblast cells in the ectoplacental cone to form the spongiotrophoblast cell layer of the mature chorioallantoic placenta.
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