HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 78/5/832    most recent biolreprod.107.066662v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Giraldo, A. M. Articles by Bondioli, K. R. PubMed PubMed Citation Articles by Giraldo, A. M. Articles by Bondioli, K. R. Agricola Articles by Giraldo, A. M. Articles by Bondioli, K. R.

Effect of Epigenetic Modifications of Donor Somatic Cells on the Subsequent Chromatin Remodeling of Cloned Bovine Embryos¹

School of Animal Sciences,³ Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803 Revivicor, Inc.,⁵ Blacksburg, Virginia 24060 Department of Biological Sciences,⁴ Louisiana State University, Baton Rouge, Louisiana 70803

ABSTRACT

Evidence indicates that failure of nuclear transfer (NT) embryos to develop normally can be attributed, at least partially, to the use of differentiated cells as the donor karyoplast. Blastocyst production and development to term of cloned embryos has been hypothesized to differ between population doublings of the same cell line as a consequence of changes in the levels of DNA methyltransferase 1 (DNMT1) and methylated DNA during in vitro culture. The objective of this study was to determine embryo production, developmental potential, and gene expression patterns of prehatched and posthatched embryos generated using donor cells with different levels of DNMT1 transcript. Day 7 embryos generated using donor cells with high and low levels of DNMT1 mRNA were transferred to recipient cows. Embryos recovered on Day 13 were morphologically characterized or used for gene expression analysis of DNMT, INFT, and MHC1. A higher proportion of 8- to 16-cell embryos developed to the blastocyst stage when cells with low levels of DNMT1 mRNA were used as donor nuclei. Day 13 NT embryos generated using donor cells with decreased levels of DNMT1 mRNA and capable of developing beyond the 8- to 16-cell stage produced a larger number of apparently developing embryos, larger conceptuses, and a higher expression of DNMT3A transcript than NT embryos reconstructed using cells with high levels of DNMT1 mRNA. However, abnormal gene expression of DNMT, INFT, and MHC1 was noted in the majority of cloned embryos, indicating inefficient nuclear reprogramming and retarded embryo development. Furthermore, aberrant DNMT1 expression may partially contribute to the inefficient nuclear reprogramming observed in cloned embryos.

chromatin remodeling proteins, cloning, early development, gene regulation, methyltransferases, preimplantation embryos

¹Supported by grants from the Louisiana State University Board of Regents through the Board of Regents Support Fund (contract LEQSF 2005-07-RD-A-01). Approved for publication by the Director of the Louisiana Agricultural Experimental Station as manuscript 07-18-0266.

Correspondence: ²Kenneth R. Bondioli, Louisiana State University, 105 Francioni Hall, Baton Rouge, LA 70803. FAX: 225 578 3279; e-mail: kbondioli{at}agcenter.lsu.edu