Effect of follicle size on mRNA expression in cumulus cells and oocytes of Bos indicus: an approach to identify marker genes for developmental competence

Abstract

To identify the genes related to oocyte competence, we quantified transcripts for candidate genes in oocytes (H1Foo, H2A, H3A, GHR, GDF9, BMP15, OOSP1) and cumulus cells (FSHR, EGFR, GHR, PTX3, IGFII) using the follicle size model to select oocytes of better developmental quality. Follicles were dissected and distributed into four groups according to diameter as follows: 1.0-3.0, 3.1-6.0, 6.1-8.0 and >or=8.1 mm. Cumulus-oocyte complexes (COCs) were released, classified morphologically, matured, fertilised and cultured in vitro or denuded for measurement of diameter and determination of gene expression. Denuded germinal vesicle oocytes and their cumulus cells were used for gene expression analysis by reverse transcription-polymerase chain reaction. The blastocyst rate was highest for oocytes recovered from follicles>6 mm in diameter. In the oocyte, expression of the H2A transcript only increased gradually according to follicle size, being greater (P<0.05) in oocytes from follicles>or=8.1 mm in diameter than in oocytes from follicles<6.0 mm in diameter. In cumulus cells, expression of FSHR, EGFR and GHR mRNA increased with follicular size. In conclusion, we confirmed the importance of H2A for developmental competence and identified important genes in cumulus cells that may be associated with oocyte competence.

Fibroblast growth factor 10 enhances bovine oocyte maturation and developmental competence in vitro

“…Included among these were FST (Hussein et al 2006, Lee et al 2009), GDF9 (Dragovic et al 2005), JY1 (Bettegowda et al 2007) and HIST2H2AC (Dode et al 2006, Caixeta et al 2009), and BMP15 (Hussein et al 2006). Changes in overall RNA abundances are evident throughout oocyte maturation and early embryonic development in cattle and other species (Robert et al 2002), and identifying a suitable internal control (or set of controls) is imperative for proper interpretation of outcomes at these stages.…”

“…The remaining cumulus competency markers were not impacted by FGF10. Included in this work were the following transcripts: EGFR and FSHR, receptors essential for normal oocyte maturation and cumulus expansion (Assidi et al 2008, Caixeta et al 2009); HAS2, a key player in cumulus expansion (Dragovic et al 2005, Assidi et al 2008; KITLG, a component of stem cell survival and oocyte growth (Cho et al 2008); and INHBA, an inhibin subunit (Assidi et al 2008).…”

Brilliant Cresyl Blue stain selects largest oocytes with highest mitochondrial activity, maturation-promoting factor activity and embryo developmental competence in prepubertal sheep

“…The mRNA content in oocytes is affected by animal nutrition (Pisani et al 2008), follicle diameter (Caixeta et al 2009), IVM culture media (Salhab et al 2011), in vivo and in vitro conditions (Wells & Patrizio 2008) and apoptosis (Li et al 2009). Thus, mRNA stored in oocytes could represent a valuable tool as a molecular marker for oocyte quality.…”

Identification of an ionotropic glutamate receptor AMPA1/GRIA1 polymorphism in crossbred beef cows differing in fertility12

“…In humans, PTX3 mRNA abundance in the cumulus cells was reported to be a marker of oocyte competence (Zhang et al, 2005), and women carrying a polymorphism in the PTX3 gene had greater fertility (May et al, 2010). There was no change in PTX3 mRNA abundances in bovine cumulus cells as follicle diameter increased, suggesting that PTX3 could be a marker of inherent oocyte competence at all stages of follicular development (Caixeta et al, 2009). The oocyte-derived growth factor growth and differentiation factor-9 (GDF-9) stimulated production of PTX3 in cultured mouse mural granulosa cells, and PTX3 mRNA abundances were decreased in the granulosa cells of transgenic mice that did not produce GDF-9 compared with wild-type controls (Varani et al, 2002).…”