Placental overgrowth in mice lacking the imprinted gene Ipl

摘要

The Ipl (Tssc3) gene lies in an extended imprinted region of distal mouse chromosome 7, which also contains the Igf2 gene. Expres- sion of Ipl is highest in placenta and yolk sac, where its mRNA is derived almost entirely from the maternal allele. Ipl encodes a small cytoplasmic protein with a pleckstrin-homology (PH) domain. We constructed two lines of mice with germ-line deletions of this gene (Ipl~neo and Ipl~loxP) and another line deleted for the similar but nonimprinted gene Tih1. All three lines were viable. There was consistent overgrowth of the Ipl-null placentas, with expansion of the spongiotrophoblast.