Gamete Biology

Poly(A) RNA Is Reduced by Half During Bovine Oocyte Maturation but Increases when Meiotic Arrest Is Maintained with CDK Inhibitors

Abstract
The variations in the amount of different RNA species were investigated during in vitro maturation of the bovine oocyte. The total RNA content was estimated to be 2ng before and after meiosis resumption, no decrease was observed. The ribosomal RNA did not appear to be degraded either whereas the poly(A) RNA was reduced by half after meiosis resumption, from 53pg to 25pg per oocyte. Real-time PCR were performed on growth and differentiation factor-9 (GDF-9), on cyclin B1 and on two genes implied in the resistance to oxidative stress, glucose-6-phosphate-dehydrogenase (G6PDH) and peroxiredoxin-6 (PRDX-6). When these transcripts were reverse-transcribed with hexamers, the amplification results were not different before and after in vitro maturation. But, if the reverse transcription was performed with oligo(dT), the amplification was dramatically reduced after maturation, except for cyclin B1 mRNA, implying deadenylation without degradation of three transcripts. Although calf oocytes have a lower developmental competence, their poly(A) RNA content was not different from cow oocytes, nor differently affected during maturation. When bovine oocytes were maintained in vitro under meiotic arrest with CDK inhibitors, their poly(A) RNA amount increased but this rise did not change the poly(A) RNA level once maturation was achieved. The increase could not be observed under transcription inhibition and, when impeding transcription and adenylation, the poly(A) RNA decreased to a level normally observed after maturation, in spite of the maintenance of meiotic arrest. These results demonstrate the importance of adenylation and deadenylation processes during in vitro maturation of bovine oocytes.

Key words: Gamete Biology • Gene regulation • Kinases • Meiosis • Oocyte development

This article has been cited by other articles:

				G. M. Jones, D. S. Cram, B. Song, M. C. Magli, L. Gianaroli, O. Lacham-Kaplan, J. K. Findlay, G. Jenkin, and A. O. Trounson Gene expression profiling of human oocytes following in vivo or in vitro maturation Hum. Reprod., May 1, 2008; 23(5): 1138 - 1144. [Abstract] [Full Text] [PDF]

				S. Uzbekova, Y. Arlot-Bonnemains, J. Dupont, R. Dalbies-Tran, P. Papillier, S. Pennetier, A. Thelie, C. Perreau, P. Mermillod, C. Prigent, et al. Spatio-Temporal Expression Patterns of Aurora Kinases A, B, and C and Cytoplasmic Polyadenylation-Element-Binding Protein in Bovine Oocytes During Meiotic Maturation Biol Reprod, February 1, 2008; 78(2): 218 - 233. [Abstract] [Full Text] [PDF]

				R. S Oliveri, M. Kalisz, C. K. Schjerling, C. Y. Andersen, R. Borup, and A. G. Byskov Evaluation in mammalian oocytes of gene transcripts linked to epigenetic reprogramming Reproduction, October 1, 2007; 134(4): 549 - 558. [Abstract] [Full Text] [PDF]

				S.-W. Dessie, F. Rings, M. Holker, M. Gilles, D. Jennen, E. Tholen, V. Havlicek, U. Besenfelder, V. L Sukhorukov, U. Zimmermann, et al. Dielectrophoretic behavior of in vitro-derived bovine metaphase II oocytes and zygotes and its relation to in vitro embryonic developmental competence and mRNA expression pattern Reproduction, May 1, 2007; 133(5): 931 - 946. [Abstract] [Full Text] [PDF]

				J. L. Edwards, A. M. Saxton, J. L. Lawrence, R. R. Payton, and J. R. Dunlap Exposure to a Physiologically Relevant Elevated Temperature Hastens In Vitro Maturation in Bovine Oocytes J Dairy Sci, December 1, 2005; 88(12): 4326 - 4333. [Abstract] [Full Text] [PDF]

				K. Tremblay, C. Vigneault, S. McGraw, and M.-A. Sirard Expression of Cyclin B1 Messenger RNA Isoforms and Initiation of Cytoplasmic Polyadenylation in the Bovine Oocyte Biol Reprod, April 1, 2005; 72(4): 1037 - 1044. [Abstract] [Full Text] [PDF]

				J. Yao, X. Ren, J. J. Ireland, P. M. Coussens, T. P. L. Smith, and G. W. Smith Generation of a bovine oocyte cDNA library and microarray: resources for identification of genes important for follicular development and early embryogenesis Physiol Genomics, September 16, 2004; 19(1): 84 - 92. [Abstract] [Full Text] [PDF]