Transcript profiling during mouse oocyte development and the effect of gonadotropin priming and development in vitro

Area of Science:

• Reproductive Biology
• Developmental Biology
• Genomics

Background:

• The molecular mechanisms driving oocyte maturation and developmental competence remain largely uncharacterized.
• Acquisition of these competences is essential for successful fertilization and embryonic development.

Purpose of the Study:

• To investigate global gene expression changes during oocyte development.
• To identify molecular processes underlying meiotic and developmental competence acquisition.

Main Methods:

• Microarray analysis of oocyte gene expression across various follicular stages (primordial to large antral).
• Expression Analysis Systematic Explorer (EASE) for identifying biological and molecular pathways.
• Comparison of in vivo and in vitro oocyte development transcriptomes.
• Assessment of eCG priming effects on oocyte gene expression and developmental competence.

Main Results:

• Significant gene expression shifts occur during the primordial to primary follicle transition.
• Specific chromosomal regions show altered transcriptional activity.
• In vitro-developed oocytes exhibit minimal transcriptomic differences compared to in vivo counterparts.
• eCG priming enhances oocyte developmental competence, correlating with reduced expression of basal transcription genes.

Conclusions:

• Oocyte development involves dynamic, stage-specific gene expression changes, with key transitions occurring early.
• Transcriptional regulation, including regional chromosomal activity, plays a critical role in acquiring oocyte competence.
• In vitro oocyte maturation protocols largely preserve the in vivo transcriptomic profile.
• Hormonal priming (eCG) can optimize oocyte developmental potential by modulating specific gene expression patterns.