Determination by Real-Time RT-PCR of Imprinted Expression of the Insulin-Like Growth Factor II (Igf2) Gene in Mouse Uniparental Fetuses.

Abstract

Abstract. Uniparental mouse embryos are generally used in the study of imprinting mechanisms as models to determine parental expression of imprinted genes. In this study, we used the real-time RT-PCR method to carry out a quantitative analysis of the expression of the insulin-like growth factor II (Igf2) gene, which is imprinted and expressed solely from the paternal allele, in androgenetic and parthenogenetic fetuses at day 9.5 of gestation. The mean expression, relative to that of control biparental fetuses, was detected to be 319% (90 to 585%) in androgenetic fetuses and 5.9% (3.7 to 9.5%) in parthenogenetic fetuses. The present results confirm that parental-specific expression of the Igf2 gene is maintained in uniparental fetuses, and also show that the real-time RT-PCR procedure is an effective method for quantitative analysis of gene expression using amounts of mRNA that are too small for other methods to detect.

Unregulated Expression of the Imprinted Genes H19 and Igf2r in Mouse Uniparental Fetuses

“…We previously reported that the expression of the paternally expressed gene Igf2 in androgenetic fetuses was slightly accelerated to 1.5 times the expected value (31). Surprisingly, however, in the present study the expressions of the H19 and Igf2r genes in parthenogenetic fetuses were more than two and six times the expected values, respectively, and the expressions were far different from that of the Igf2 gene in androgenetic fetuses.…”

Disruption of Imprinted Expression ofU2afbp-rs/U2af1-rs1 Gene in Mouse Parthenogenetic Fetuses

“…DISCUSSION We reported previously that expressions of mouse paternally expressed imprinted genes Peg1/Mest (16), Igf2 (14), Peg3 (18), and Snrpn (29) are not properly detected by RT-PCR in mouse parthenogenetic fetuses at day 9.5 of gestation (30). Further analysis by real-time quantitative RT-PCR confirmed parental specific expression of the Igf2 gene in both the parthenogenetic and androgenetic fetuses (31). These previously published observations show that parental expression of imprinted genes is generally maintained in uniparental fetuses.…”

“…Many imprinted genes, such as Igf2, Igf2r, Peg1/Mest, Peg3, and H19, maintain their parental specific expression in uniparental embryos (13,16,18,31,35), that is, in parthenogenetic/ gynogenetic and androgenetic embryos. However, the present results show that this is not the case for the U2afbp-rs.…”