Messenger RNA expression patterns of histone‐associated genes in bovine preimplantation embryos derived from different origins

Abstract

Histone modification genes in bovine embryos: The mRNA expression pattern of histone-related genes was determined in bovine oocytes and embryos. We compared immature and in vitro-matured oocytes, either before or after enucleation and activation, in vitro produced embryos (zygotes, 8-16 cell stages, blastocysts), embryos cloned with female or male donor cells; parthenogenetic embryos, and in vivo-derived blastocysts to detect deviations from the normal expression pattern. A sensitive semi-quantitative endpoint RT-PCR assay was used to reveal differences in histone deacetylation [histone deacetylase 2 (HDAC2)]; histone acetylation [histone acetyltransferase 1 (HAT1)]; histone methylation [histone methyltransferases (SUV39H1, G9A)]; heterochromatin formation [heterochromatin protein 1 (HP1)]; and chromatin-mediated transcription regulation [zygote arrest 1 (ZAR1)]. With the exception of ZAR1, these mRNAs were present throughout preimplantation development. The relative abundance of mRNAs for histone methyltransferases (SUV39H1 and G9A) and for heterochromatin-associated protein (HP1) differed significantly before and after activation of the bovine embryonic genome. The similarity of HAT1 gene expression in 8-16 cell embryos and blastocysts suggests that histone acetylation is primarily affected by in vitro culture only prior to embryonic genome activation. HDAC2 gene mRNA expression was not affected by in vitro culture and/or cloning before and after activation of the embryonic genome. The donor cell line affected mRNA expression patterns of genes involved in reprogramming cloned embryos suggesting epigenetic dysregulation. Results show that both in vitro production and somatic cloning alter the mRNA expression of histone modifying genes in bovine embryos. Mol.

DNA methylation and mRNA expression profiles in bovine oocytes derived from prepubertal and adult donors

“…Similar findings were made for ZAR1, an important maternal effect gene regulating early embryonic development (Duranthon & Renard 2001, Brevini et al 2004. ZAR1transcripts have been found in immature oocytes and in early embryos until major activation of the embryonic genome (Brevini et al 2004, Nowak-Imialek et al 2008). …”

Histone modifications during mammalian oocyte maturation: Dynamics, regulation and functions

“…41 Remarkably, accompanying with meiotic maturation, the relative abundance of SUV39H1 dramatically decreased in mouse and bovine oocyte. 69,70 G9A transcripts were absent in immature and matured mouse oocytes 70 and downregulated in bovine oocytes. 41,69 PcG proteins enhancer of zeste2 (EZH2) is one of HMTs responsible for methylating H3/K27.…”

“…69,70 G9A transcripts were absent in immature and matured mouse oocytes 70 and downregulated in bovine oocytes. 41,69 PcG proteins enhancer of zeste2 (EZH2) is one of HMTs responsible for methylating H3/K27. 71 Park et al found that the expression of EZH2 mRNA slightly reduced during porcine oocyte maturation.…”

Proteomic analysis of the major cellular proteins of bovine trophectoderm cell lines derived from IVP, parthenogenetic and nuclear transfer embryos: Reduced expression of annexins I and II in nuclear transfer-derived cell lines

“…The gene expression of embryos and fetuses produced by normal fertilization with sperm in comparison with embryos produced by NT shows numerous differences (Wrenzycki et al, 2001;Nowak-Imialek et al, 2008;Perecin et al, 2009). Conservation of appropriate DNA methylation patterns appears to be a problem in NT embryos (Bourc'his et al, 2001;Kang et al, 2002;Cezar et al, 2003;Santos et al, 2003).…”