Differential expression of genes for transcription factors in theca and granulosa cells following selection of a dominant follicle in cattle.

Transcription factors inhibit or assist RNA polymerases in the initiation and maintenance of transcription; however, the cell specific expression and roles of transcription factors within bovine ovarian follicles during development are unknown. The aim of present study was to determine if the expression of transcription factors in theca and granulosa cells differ between the dominant and the largest subordinate follicles at different stages of the follicle wave. We used a bovine cDNA microarray to screen granulosa and theca cells from dominant and subordinate follicles for differential expression of genes coding for transcription factors. Expression was confirmed using reverse transcription polymerase chain reaction and differences in mRNA abundance further examined at Emergence, Selection and Dominance stages of the follicle wave. We have identified five genes encoding for transcription factors that have not been previously described in developing follicles with greater mRNA abundance in subordinate compared to dominant follicles. The genes (and their putative roles) are CEBP-beta (responsible for luteinization), SRF (cell survival), FKHRL1 (stimulates apoptosis), NCOR1 (modulation of the actions of the oestradiol receptor) and Midnolin (control of development via regulation of mRNA transport in cells). (c) 2007 Wiley-Liss, Inc.