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) 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bordignon, V. Articles by Smith, L. C. Search for Related Content PubMed PubMed Citation Articles by Bordignon, V. Articles by Smith, L. C. Agricola Articles by Bordignon, V. Articles by Smith, L. C.

Ultraviolet-Irradiated Spermatozoa Activate Oocytes but Arrest Preimplantation Development After Fertilization and Nuclear Transplantation in Cattle¹

^a Centre de recherche en reproduction animale (CRRA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Canada J2S 7C6

Artificial means of parthenogenetically activating mammalian oocytes are believed to lack an essential sperm epigenetic component required for normal development. The main goal of this study was to examine the potential of ultraviolet (UV)-irradiated sperm as a means of functionally eliminating the chromatin component of spermatozoa without affecting the ability to induce activation and support parthenogenetic development in cattle. Spermatozoa were stained with a DNA dye, exposed to various UV irradiation doses, and used to fertilize secondary oocytes. Although the percentage of pronuclei at 18 h postinsemination was similar using treated and control sperm, most oocytes fertilized by UV-irradiated sperm failed to develop beyond the 2-cell stage, suggesting that UV irradiation can functionally destroy the genomic component of spermatozoa with limited effects on the ability to induce oocyte activation. However, when oocytes activated with UV-irradiated sperm were used as hosts for nuclear transfer, developmental rates to cleavage and to blastocyst improved only marginally and remained lower than in the controls, indicating that UV-treated spermatozoa blocked development even in the presence of a diploid donor nucleus. Although DNA replication was not inhibited by UV irradiation treatment, abnormal chromatin morphology after cleavage suggests improper segregation of chromatin to daughter blastomeres during the first mitotic division. Together, these results indicate that although sperm exposed to UV can activate oocytes, a developmental block occurs at or soon after the first mitosis in parthenotes and oocytes reconstructed by nuclear transfer.

¹ This work was supported by the National Science and Engineering Research Council (NSERC) of Canada. V.B. was supported by a scholarship from CNPq, Brazil.

² Correspondence: Lawrence C. Smith, Centre de recherche en reproduction animale (CRRA), Faculté de médecine vétérinaire, Université de Montréal, C.P. 5000, Saint-Hyacinthe, Canada J2S 7C6. FAX: 450 778 8103; smithl{at}medvet.umontreal.ca

This article has been cited by other articles:

				A. N. Fatehi, M. M. Bevers, E. Schoevers, B. A. J. Roelen, B. Colenbrander, and B. M. Gadella DNA Damage in Bovine Sperm Does Not Block Fertilization and Early Embryonic Development But Induces Apoptosis After the First Cleavages J Androl, March 1, 2006; 27(2): 176 - 188. [Abstract] [Full Text] [PDF]

				J. A. Desmarais, V. Bordignon, F. L. Lopes, L. C. Smith, and B. D. Murphy The Escape of the Mink Embryo from Obligate Diapause Biol Reprod, March 1, 2004; 70(3): 662 - 670. [Abstract] [Full Text] [PDF]