This Article Full Text Full Text (PDF) Supplementary Figures All Versions of this Article: 136/6/777    most recent REP-08-0045v1 Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Ross, P. J Articles by Cibelli, J. B Search for Related Content PubMed PubMed Citation Articles by Ross, P. J Articles by Cibelli, J. B

Polycomb gene expression and histone H3 lysine 27 trimethylation changes during bovine preimplantation development

Departments of¹ , Animal Science² Physiology, Michigan State University, East Lansing, Michigan 48824, USA³ Animal Production Unit, Department of Agriculture, Public University of Navarra, Pamplona, Navarra 31006, Spain⁴ Programa Andaluz de Terapia Celular y Medicina Regenerativa, Andalucía, Spain

Correspondence should be addressed to J B Cibelli; Email: cibelli{at}msu.edu

Trimethylation of histone H3 at lysine 27 (H3K27me3) is established by polycomb group genes and is associated with stable and heritable gene silencing. The aim of this study was to characterize the expression of polycomb genes and the dynamics of H3K27me3 during bovine oocyte maturation and preimplantation development. Oocytes and in vitro-produced embryos were collected at different stages of development. Polycomb gene expression was analyzed by real-time quantitative RT-PCR and immunofluorescence. Global H3K27me3 levels were determined by semiquantitative immunofluorescence. Transcripts for EZH2, EED, and SUZ12 were detected at all stages analyzed, with EZH2 levels being the highest of the three at early stages of development. By the time the embryo reached the blastocyst stage, the level of PcG gene mRNA levels significantly increased. Immunofluorescence staining indicated nuclear expression of EZH2 at all stages while nuclear localized EED and SUZ12 were only evident at the morula and blastocyst stages. Semiquantitative analysis of H3K27me3 levels showed that nuclear fluorescence intensity was the highest in immature oocytes, which steadily decreased after fertilization to reach a nadir at the eight-cell stage, and then increased at the blastocyst stage. These results suggest that the absence of polycomb repressive complex 2 proteins localized to the nucleus of early embryos could be responsible for the gradual decrease in H3K27me3 during early preimplantation development.

This article has been cited by other articles:

				R. K. Auerbach, G. Euskirchen, J. Rozowsky, N. Lamarre-Vincent, Z. Moqtaderi, P. Lefrancois, K. Struhl, M. Gerstein, and M. Snyder Mapping accessible chromatin regions using Sono-Seq PNAS, September 1, 2009; 106(35): 14926 - 14931. [Abstract] [Full Text] [PDF]

				P. J Ross, R. M Rodriguez, A. E Iager, Z. Beyhan, K. Wang, N. P Ragina, S.-Y. Yoon, R. A Fissore, and J. B Cibelli Activation of bovine somatic cell nuclear transfer embryos by PLCZ cRNA injection Reproduction, March 1, 2009; 137(3): 427 - 437. [Abstract] [Full Text] [PDF]