Imprinted Gene mRNA Expression during Porcine Peri-implantation Development

Abstract

Imprinted genes are essential for fetal development, growth regulation, and postnatal behavior. However, little is known about imprinted genes in livestock. We hypothesized that certain putatively imprinted genes affected normal peri-implantation development such as embryo elongation, initial placental development, and preparation of implantation. The objective of the present study was to investigate the mRNA expression patterns of several putatively imprinted genes during the porcine peri-implantation stages from day 6 to day 21 of gestation. Imprinted genes were selected both maternally (Dlk1, IGF2, Ndn, and Sgce) and paternally (IGF2r, H19, Gnas and Xist). Here, we report that the maternally imprinted gene IGF2 was expressed from day 6 (Blastocyst stage), but Dlk1, Ndn, and Sgce were not expressed in this stage. These genes were first expressed between days 12 and day 14. All the maternally imprinted genes studied showed significantly high expression patterns from day 18 of embryo development. In contrast, paternally imprinted genes IGF2r, H19, Gnas, and Xist were first expressed from day 6 of embryo development (BL). Our data demonstrated that the expression of H19 and Gnas genes was significantly increased from day 14 of the embryo developmental stage, while IGF2r and Xist only showed high expression after day 21. This study is the first to show that the putatively imprinted genes were stage-specific during porcine embryonic development. These results demonstrate that the genes studied may exert important effects on embryo implantation and fetal development.

Expression Profiles of the Insulin-like Growth Factor System Components in Liver Tissue during Embryonic and Postnatal Growth of Erhualian and Yorkshire Reciprocal Cross F1 Pigs

“…On the other hand, both IGF-2 and IGF-2R are imprinted genes in pigs. IGF-2 has been reported to be paternally expressed, while IGF-2R is maternally expressed ( Nezer et al, 1999 ; Killian et al, 2001 ; Bischoff et al, 2009 ; Cha et al, 2010 ). If a gene is imprinted, the relative allelic expression activity and even individual phenotype may be different in progeny of reciprocal crosses ( Chaillet 1994 ; Curley and Keverne, 2004 ; Wittkopp et al, 2006 ).…”

“…At the same time, the IGF-2R gene is paternally imprinted in rodents, artiodactyls and marsupials, but is biallelically expressed in primates ( Killian et al, 2000 ). In pigs, it has been shown that IGF-2R is maternally expressed ( Killian et al, 2001 ; Bischoff et al, 2009 ; Cha et al, 2010 ).…”