Protein synthesis and phosphorylation patterns of bovine oocytes maturing in vivo

Abstract

To investigate protein synthesis and phosphorylation during bovine oocyte maturation in vivo, oocytes were collected at consecutive times after the preovulatory luteinizing hormone (LH) peak. Therefore, heifers treated for superovulation were ovariectomized between 3 and 20 h after the maximum of the LH peak. Subsequently, cumulus-enclosed oocytes, selected from nonatretic follicles greater than 10 mm, were radiolabeled with 35S-methionine or 32P-orthophosphate for 3 h and individually prepared for gel electrophoresis. Changes in the protein synthesis patterns were observed coinciding with germinal vesicle breakdown (GVBD). No changes were detected during the ensuing maturation period or coinciding with the extrusion of the first polar body. In addition, the protein phosphorylation patterns exhibited striking differences around GVBD. In particular, a phosphoprotein band of 19 kDa and the two heavily phosphorylated proteins with apparent molecular weights between 50 and 60 kDa were present in patterns of oocytes in the germinal vesicle stage. The results are discussed in relation to previous data obtained during maturation in vitro.

Raman Micro-Spectroscopy Can Be Used to Investigate the Developmental Stage of the Mouse Oocyte

“…The results of the PCA here revealed that oocytes developed in vitro had lower spectral contributions arising from protein vibrations than ovulated oocytes whether obtained from natural ovulations of following a superovulation regimen. These data are consistent with the findings of several authors who have reported lower protein expression in in vitro matured murine [26], bovine [27] and human [28] oocytes, when compared to their in vivo matured counterparts. In certain instances, some proteins were found to be absent in the in vitro developed oocytes, whilst Kim et al [26] specifically identified significantly reduced expression of β-actin and insulin-like growth factor II.…”

Meiotic Arrest In Vitro by Phosphodiesterase 3-Inhibitor Enhances Maturation Capacity of Human Oocytes and Allows Subsequent Embryonic Development1

“…Despite the fact that nuclear and cytoplasmic maturation of oocytes can proceed independently, both processes need to be coordinated to ensure developmental competence. The path to attain cytoplasmic competence includes buildup and storage of transcripts [1,2], synthesis and accumulation of proteins [3], posttranslational modifications [4], and ultrastructural changes [5]. In primates, cytoplasmic maturation is acquired in fully grown oocytes during the later stages of follicle development [6].…”

Improvement of in vitro oocyte maturation with lectin supplementation and expression analysis of Cx43, GDF-9, FGF-4 and Fibronectin mRNA transcripts in Buffalo (Bubalus bubalis)

“…Five levels of oocyte developmental competence were characterized by Sirard et al [3] including the ability to resume meiosis, to cleave upon fertilization, to develop into blastocysts, to induce pregnancy and to generate healthy offspring. Cytoplasmic changes accompanying oocyte growth include mRNA transcription, protein translation and post translational modification [4,5]. Oocytes are complex cells comprising many organelles and molecules, each of which must be in the appropriate state for the egg to be competent to sustain subsequent embryo development [6].…”