GATM, the human ortholog of the mouse imprinted Gatm gene, escapes genomic imprinting in placenta

Abstract

The GATM gene encodes L-arginine:glycine amidinotransferase, which catalyzes the conversion of L-arginine into guanidinoacetate, the rate-limiting step in the synthesis of creatine. Since, deficiencies in creatine synthesis and transport lead to certain forms of mental retardation in human, the human GATM gene appears to be involved in brain development. Recently it has been demonstrated that the mouse Gatm is expressed during development and is imprinted with maternal expression in the placenta and yolk sac, but not in embryonic tissues. We investigated the imprinting status of the human GATM by analyzing its expression in four human placentas. GATM was biallelically expressed, thus suggesting that this gene escapes genomic imprinting in placentas, differently from what has been reported in mouse extra-embryonic tissues.

Imprinting analyses of the porcine GATM and PEG10 genes in placentas on days 75 and 90 of gestation

“…Thus, the conservation of imprinted genes across different mammalian species is a special phenomena comparing to other organisms such as plants. Our data showed biallelic expression of GATM in the placenta of pig in two different developmental stages, this was in agreement with the result from human placenta, which had been confirmed to escape genomic imprinting (Miyamoto et al, 2005). This demonstrated that GATM in extant mammals has divergent imprint status.…”

“…E-mail: shzhao@mail.hzau.edu.cn and expresses exclusively from the maternal allele (Sandell et al, 2003). However, GATM escapes genomic imprinting in human placenta (Miyamoto et al, 2005). Paternally expressed gene 10 (PEG10), as an endogenous gene, is expressed extensively in some embryonic tissues as well as in the placenta (Ono et al, 2001).…”