Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The Mechanism of Oocyte Activation Influences the Cell Cycle-Related Genes Expression During Bovine Preimplantation Development

Full text
Author(s):
Milazzotto, Marcella Pecora [1] ; Feitosa, Weber Beringui [2] ; Paula-Lopes, Fabiola Feitosa [3] ; Buratini, Jr., Jose [4] ; Visintin, Jose Antonio [2] ; Assumpcao, Mayra E. O. A. [2]
Total Authors: 6
Affiliation:
[1] Univ Fed ABC, Nat & Human Sci Ctr, Santo Andre, SP - Brazil
[2] Univ Sao Paulo, Dept Anim Reprod, Fac Vet Med, Sao Paulo - Brazil
[3] Univ Fed Sao Paulo, Dept Biol Sci, Diadema, SP - Brazil
[4] UNESP, Dept Physiol, Inst Biosci, Botucatu, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: CELLULAR REPROGRAMMING; v. 14, n. 5, p. 418-424, OCT 2012.
Web of Science Citations: 3
Abstract

The first cleavage divisions and preimplantation embryonic development are supported by mRNA and proteins synthesized and stored during oogenesis. Thus, mRNA molecules of maternal origin decrease and embryonic development becomes gradually dependent on expression of genetic information derived from the embryonic genome. However, it is still unclear what the role of the sperm cell is during this phase and whether the absence of the sperm cell during the artificial oocyte activation affects subsequent embryonic development. The objective of this study was to determine, in bovine embryos, changes in cell cycle-associated transcript levels (cyclin A, cyclin B, cyclin E, CDC2, CDK2, and CDK4) after oocyte activation in the presence or absence of the sperm cell. To evaluate that, in vitro-produced (IVP) and parthenogenetically activated (PA) embryos (2-4 cells (2-4C), 8-16 cells (8-16C) and blastocysts) were evaluated by real-time PCR. There was no difference in cleavage and blastocyst rates between IVP and PA groups. Transcript level was higher in oocytes than in IVP and PA embryos. Cleaved PA embryos showed higher expression of cyclin A, cyclin B, cyclin E, and CDK2 and lower expression of CDC2 when compared with that from the IVP group. At the time of activation, all transcripts were expressed less in PA than in IVP embryos, whereas at the blastocyst stage, almost all genes were expressed at a higher level in the PA group. These results suggest that in both groups there is an initial consumption of these transcripts in the early stages of embryonic development. Furthermore, 8-16C embryos seem to synthesize more cell cycle-related genes than 2-4C embryos. However, in PA embryos, activation of the cell cycle genes seems to occur after the 8- to 16-cell stage, suggesting a failure in the activation process. (AU)