Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.22 (cdc2)
 8,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Delineation of maternal versus direct effects of heat stress in reducing development at the germinal vesicle (GV) stage is challenging, because oocytes spontaneously resume meiosis after removal from antral follicles. The use of S-roscovitine (inhibitor of p34(cdc2)/cyclin B kinase) to hold bovine oocytes at the GV stage without compromising early embryo development was previously validated in our laboratory. The objective of the present study was to assess the direct effects of an elevated temperature commonly seen in heat-stressed dairy cows on cumulus-oocyte complexes (COCs) held at the GV stage using 50 microM S-roscovitine. During roscovitine culture, GV-stage COCs (antral follicle diameter, 3-8 mm) were cultured at 38.5 or 41 degrees C. Thereafter, oocytes were removed from roscovitine medium and allowed to undergo in vitro maturation, fertilization, and culture. Zona pellucida hardening (solubility to 0.5% pronase), nuclear stage (Hoechst 33342), cortical granule type (lens culinaris agglutinin-fluorescein isothiocyanate [FITC]), and early embryo development were evaluated. Culture of GV-stage COCs at 41 degrees C increased the proportion that had type III cortical granules and reduced the proportion that progressed to metaphase II after in vitro maturation. Effects of 41 degrees C on zona pellucida hardening, fertilization (penetration, sperm per oocyte, pronuclear formation, and monospermic and putative embryos), and cleavage of putative zygotes were not noted. However, culture of GV-stage COCs at 41 degrees C for 6 h decreased the proportion of 8- to 16-cell embryos, whereas 41 degrees C for 12 h reduced blastocyst development. In summary, antral follicle COCs are susceptible to direct effects of elevated body temperature, which may account in part for reduced fertility in heat-stressed cows.
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PMID:Susceptibility of bovine germinal vesicle-stage oocytes from antral follicles to direct effects of heat stress in vitro. 1520 Dec 1

The present study was conducted to investigate the relation between in vitro developmental competence and the expression of a panel of developmentally important genes in germinal vesicle (GV) stage oocytes. One-month-old prepubertal and adult sheep oocytes were used as models of low and high quality gametes, respectively. Cumulus-oocyte complexes (COCs) derived from lambs and ewes were in vitro matured and fertilized, and their cleavage rate at 22, 26, and 32 hr post fertilization and the blastocyst yield were observed to assess their developmental potential. In parallel, the relative abundance (RA) of 11 genes was analyzed by semi-quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR) assay in the two groups of oocytes. We observed similar maturation and fertilization rates in the two groups, but a significant lower rate of cleaved prepubertal oocytes (P < 0.05), a general delay in the timing of their first division (P < 0.01), and a lower blastocysts production (P < 0.05). The analysis of gene expression evidenced no difference in the RA of four transcripts [superoxide dismutase (SOD), ubiquitin, beta-actin, cyclin B] in the two classes of oocytes, but a statistically lower RA of seven messenger RNAs (mRNA) [Na(+)K(+)ATPase, p34(cdc2), Glucose-transporter I (Glut-1), Activin, Zona Occludens Protein 2 (PanZO2), Poli(A)Polymerase (PAP), E-Cadherin (E-Cad)] in the prepubertal oocytes compared to the adult ones. The present data show for the first time in the ovine species that the lower developmental competence is associated with deficiencies in the mRNAs storage during the oocyte growth.
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PMID:Relations between relative mRNA abundance and developmental competence of ovine oocytes. 1694 75