Abstract: Abstract:【Objective】Several layers of cumulus cells surround the oocyte in the antral follicle and play an important support and regulation role in oocytes development and maturation via the intercellular communications and interactions between oocytes and cumulus cells. The studies were conducted to investigate the function of cumulus cells during in vitro maturation of porcine oocytes and the gene expression profiles between cumulus-oocyte complexes (COCs) and naked oocytes (NOs) 【Method】Using differential display reverse transcriptase polymerase chain reaction (DD-RT-PCR) analysis of differential mRNA expression and semi-quantitative reverse transcriptase-polymerase chain reaction, we compared mRNA expression in porcine oocytes from two sources:COCs and NOs. Fourteen differentially expressed cDNAs were cloned, sequenced, and their expression patterns were verified by semi-quantitative RT-PCR. 【Result】Four cDNAs, including three genes (PELP1, Myo5b and CAST) and a new EST were confirmed preferentially expressed in the oocytes of COCs than NOs. The studies of three differentially expressed genes suggested that they mainly involved in estrogen receptor regulation, membrane trafficking, organelle transport, cellular signaling and a variety of other cellular processes. These results suggest that the aberrant transcription patterns detected in the oocytes of NOs compared with COCs may explain their reduced qualities in term of development and maturation. 【Conclusion】These differentially transcripted cDNAs may involved in the cellular interactions between oocytes and cumulus cells and thus to be considered as essential genes for the competence of oocytes.

Key words: Porcine oocyte, In vitro maturation, Differential display, Cumulus, naked oocytes