Penkov L I, Kondrakhina M S, Mironova O V, Platonov E S
Genetika. 2008 Aug;44(8):1148-52.
The effect of transforming growth factor alpha (TGFt) on the expression of imprinted Igf2 and Peg1/Mest genes was studied in diploid parthenogenetic embryos (PEs) of (CBA x C57BL/6)F1 mice during the postimplantation period of embryogenesis. The PEs were treated with TGFalpha in vitro at the morula stage and, after they developed to the blastocyst stage, were implanted into the uterus of false-pregnant females. On the tenth day of pregnancy, the PEs were explanted for subsequent in vitro culturing for 24 or 48 h. The expression of the imprinted Igf2 and Peg1/Mest genes was studied by means of whole mount in situ hybridization using digoxigenin-labeled antisense RNAs. The expression of the imprinted Igf2 and Peg1/Mest genes was studied in embryos on the tenth day of in utero development before culturing and after 24 and 48 h of culturing in vitro. The expression of Igf2 before culturing was detected only in the brain of 60% of PEs on the tents day of pregnancy (the 21-to 25-somite stages); while the Peg1/Mest expression was not detected at all. In control (not treated with TGFalpha) PEs, neither gene was expressed at the same 21- to 25-somite stages. After 24 h of culturing, the Igf2 expression was detected in the brain of 71% of PEs at the 30- to 35-somite stages, while the Peg1/Mest expression was not detected. In control (untreated) PEs, neither imprinted gene was expressed at the 30- to 35-somite stage. After 48 h of culturing, Igf2 was expressed in the regions of the brain, developing jaws, heart, liver, and somites of all TGFalpha-treated PEs at the 40- to 45-somite stages; and Peg1/Mest was expressed in the brain, heart, and liver of these embryos. In control (untreated) PEs, neither Igf2 nor Peg1/Mest was expressed at these stages The expression patterns of the imprinted Igf2 and Peg1/Mest genes in PEs at the most advanced developmental stages (40-45 somites) and in normal (fertilized) embryos at the same stages were similar; however, their expression rate in PEs was substantially lower than in normal embryos. These data indicate that exogenous TGFalpha can reactivate the expression of the two imprinted genes, modulating the effects of genomic imprinting in such a way that the PE development is improved and substantially prolonged.
在（CBA×C57BL/6）F1小鼠二倍体孤雌生殖胚胎（PEs）胚胎发生的植入后阶段，研究了转化生长因子α（TGFα）对印记基因Igf2和Peg1/Mest表达的影响。在桑椹胚阶段对PEs进行体外TGFα处理，待其发育至囊胚阶段后，植入假孕雌性小鼠子宫。在妊娠第10天，将PEs取出进行后续24或48小时的体外培养。通过使用地高辛标记的反义RNA进行全胚胎原位杂交，研究印记基因Igf2和Peg1/Mest的表达。在子宫内发育第10天的胚胎培养前以及体外培养24和48小时后，研究印记基因Igf2和Peg1/Mest的表达。培养前，仅在妊娠第10天（21至25体节阶段）60%的PEs的脑中检测到Igf2表达；而Peg1/Mest表达完全未检测到。在对照（未用TGFα处理）的PEs中，在相同的21至25体节阶段这两个基因均未表达。培养24小时后，在30至35体节阶段71%的PEs的脑中检测到Igf2表达，而Peg1/Mest表达未检测到。在对照（未处理）的PEs中，在30至35体节阶段两个印记基因均未表达。培养48小时后，在40至45体节阶段所有经TGFα处理的PEs的脑、发育中的颌、心脏、肝脏和体节区域均检测到Igf2表达；并且Peg1/Mest在这些胚胎的脑、心脏和肝脏中表达。在对照（未处理）的PEs中，在这些阶段Igf2和Peg1/Mest均未表达。在发育最成熟阶段（40至45体节）的PEs以及相同阶段的正常（受精）胚胎中，印记基因Igf2和Peg1/Mest的表达模式相似；然而，它们在PEs中的表达率明显低于正常胚胎。这些数据表明，外源性TGFα可重新激活这两个印记基因的表达，调节基因组印记的作用，从而改善并显著延长PEs的发育。
