Modulating the Expression of Imprinted Genes in Mouse Parthenogenetic Embryos

ABSTRACT

The effect of transforming growth factor α (TGFα) on the expression of imprinted genes Igf2, H19 and Pegl/Mest in diploid parthenogenetic mouse embryos (PE) from hybrids (CBA x C57BL/6)F1 in posimplantational period of embryonal development has been studied. PE were treated with TGFα in vitro at morula stage and after development to blastocyst stage were transplanted in the uterus of pseudopregnant females. At day 10 from the begining of pregnancy PE were explanted for culturing in vitro for 48 hours. The expression of imprinted genes Igf2, H19 and Peg1/Mest was studied by the methods RT-PCR u whole mount in situ RNA-RNA hybridization by labelled with digoxygenin antisens RNA probes. It has been demonstrated, that before beginning of culturing in 60% from treated PE at day 10 (stage of 21–25 somites) expression of Igf2 has been established only in forebrain, expression of Peg1/Mest has not been established and expression of H19 was significantly diminished. In the control non-treated with TGFα PE at the same stages (21–25 somites) expression of the genes Igf2 and Peg1/Mest has not been detected. After 48 hours culture in vitro in all PE treated with TGFα and developed to stage of 40–45 somites, expression of Igf2 has been established in the cerebrum, heart, forming maxillae, liver and somites, expression of Peg1/Mest was found in the cerebrum, heart and liver. In the control non-treated with TGFα PE at similar stages of development expression of Igf2 and Peg1/Mest was not detected. The data received shows, that exogenic TGFα is able to reactivate expression of two imprinted genes (Igf2 u Peg1/Mest) and to repress third imprinted gene (H19). In this way TGFα modulates the effects of genomic imprinting and improve significantly viability and development of PE. The possibility that gene coding for TGFα is imprinted is discussed‥

Keywords:

• genomic imprinting
• parthenogenetic mouse embryos
• transforming growth factor α (TGFα)
• imprinted genes Igf2
• H19 and Peg1/Mest