Tissue- and Developmental Stage-Specific Imprinting of the Mouse Proinsulin Gene, Ins2

Abstract

We have investigated the imprinting status of two insulin genes using an interspecific recombinant congenic mouse strain carrying Ins1 and Ins2 alleles from Mus spretus on a C57BL/6 genetic background. At Days 12.5, 13.5, and 14.5 of gestation, expression of both parental alleles of both Ins1 and Ins2 was detected in the bodies of the embryos. In the heads, only Ins2 expression was detected, and, again, both parental alleles were expressed. In yolk sacs, only Ins2 transcripts were found. Both parental alleles were expressed on Day 12.5, but the expression of the maternal allele gradually declined with only the paternal allele remaining active by Day 14.5. Thus, Ins2 is subject to genomic imprinting in the yolk sac. This imprinting is not only tissue-specific, but appears to be a multistep process with postzygotic events likely to play an important role in repression of the maternal allele.

Human EGFR, a candidate gene for the Silver-Russell syndrome, is biallelically expressed in a wide range of fetal tissues

“…20 Unfortunately, although fetuses up to 18 weeks' gestation were screened, the latest stage informative fetus was of 14 weeks' gestation. Thus definition of imprinting status was confined to first and early second trimester fetal tissues.…”

“…18 No evidence of imprinting was found at a number of different stages. However, there is a growing number of reports of tissue, 19 developmental stage 20 and species-specific 21 imprinting of genes. These findings make it important to study the allele-specific expression pattern of EGFR in a number of human fetal tissues at different gestational ages to confidently rule out its involvement in the mUPD7 phenotype.…”

Large-scale studies of the HphI insulin gene variable-number-of-tandem-repeats polymorphism in relation to Type 2 diabetes mellitus and insulin release

“…However, it is uncertain whether the human INS-VNTR region is imprinted. The murine insulin gene, Ins2, is paternally expressed in the yolk sac [27], and there is also sex, age and BMI as explanatory variables and family as a random factor. BMI and age were excluded from the model when analysing birth data.…”

Imprinted genes in mouse placental development and the regulation of fetal energy stores

“…Some genes are imprinted in all cell types, while others are imprinted in only a subset (Deltour et al 1995, Hu et al 1998, Yu et al 1998, Charalambous et al 2003, Dockery et al 2009). In particular, a number of genes imprinted in the placenta are not imprinted in the embryo (Hudson et al 2010, Okae et al 2012.…”