Genovul-Bt-Ssc_020410

In mammals, ovarian folliculogenesis leading to the ovulation of completely mature oocytes is a long and complex process that is regulated at different levels. The mechanisms that underlie the selection of one or several dominant follicles as well as the regulation of the number of ovulating follicles are largely unknown. In this project, we proposed to study the genetic determinism that underlies the difference of ovulation rate between species (cattle and pigs), by studying two processes that exist in ovary: follicular development and follicular atresia. Towards this purpose, we made a comparative transcriptomics study on granulosa cells. Pig and cattle comparison was achieved by a transcriptome analysis with a 9K nylon pig microarray (GPL3729) on granulosa cells from either small healthy antral follicles (SHF), small atretic follicles (SAF) or large healthy antral follicles (LHF). The images were quantified using AGscan software and the data were managed with BASE software. Statistical analysis was performed using R software. Transcriptomic analysis on pig and cattle evidenced 997 differentially expressed genes (FDR1%) between the three follicle classes and/or the two species. This research project which implicated three laboratories from INRA: "Laboratoire de Genetique Cellulaire" (UMR444-LGC) , "Station d'Amelioration Genetique des Animaux" (UR 631-SAGA) and "Physiologie des Comportements et de la reproduction" (UMR 85-PRC) benefited from both European funding through SABRE project and French ANR funding through GenOvul project. Keywords: transcriptome analysis, pig, cattle, ovary, folliculogenesis, gene expression, cDNA microarray The data were obtained from 34 RNA samples: 10 small healthy follicles samples (6 for sows and 4 for cows), 13 small atretic follicles samples (7 for sows and 6 for cows) and 11 samples for large healthy follicles (6 for sows and 5 for cows). They were hybridized on a 9K pig nylon microarray (GPL3729).