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The Expression Pattern of microRNAs in Granulosa Cells of Subordinate and Dominant Follicles during the Early Luteal Phase of the Bovine Estrous Cycle. Salilew-Wondim D 2014 et al.
This study aimed to investigate the miRNA expression patterns in granulosa cells of subordinate (SF) and dominant follicle (DF) during the early luteal phase of the bovine estrous cycle. For this, miRNA enriched total RNA isolated from granulosa cells of SF and DF obtained from heifers slaughtered at day 3 and day 7 of the estrous cycle was used for miRNAs deep sequencing. The results revealed that including 17 candidate novel miRNAs, several known miRNAs (n?=?291-318) were detected in SF and DF at days 3 and 7 of the estrous cycle of which 244 miRNAs were common to all follicle groups. The let-7 families, bta-miR-10b, bta-miR-26a, bta-miR-99b and bta-miR-27b were among abundantly expressed miRNAs in both SF and DF at both days of the estrous cycle. Further analysis revealed that the expression patterns of 16 miRNAs including bta-miR-449a, bta-miR-449c and bta-miR-222 were differentially expressed between the granulosa cells of SF and DF at day 3 of the estrous cycle. However, at day 7 of the estrous cycle, 108 miRNAs including bta-miR-409a, bta-miR-383 and bta-miR-184 were differentially expressed between the two groups of granulosa cell revealing the presence of distinct miRNA expression profile changes between the two follicular stages at day 7 than day 3 of the estrous cycle. In addition, unlike the SF, marked temporal miRNA expression dynamics was observed in DF groups between day 3 and 7 of the estrous cycle. Target gene prediction and pathway analysis revealed that major signaling associated with follicular development including Wnt signaling, TGF-beta signaling, oocyte meiosis and GnRH signaling were affected by differentially expressed miRNAs. Thus, this study highlights the miRNA expression patterns of granulosa cells in subordinate and dominant follicles that could be associated with follicular recruitment, selection and dominance during the early luteal phase of the bovine estrous cycle.
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Transactivation of microRNA-383 by Steroidogenic Factor-1 Promotes Estradiol Release from Mouse Ovarian Granulosa Cells by Targeting RBMS1. Yin M et al. Our previous studies have shown that microRNA-383 (miR-383) is one of the most down-regulated miRNA in TGF-?-treated mouse ovarian granulosa cells (GC). However, the roles and mechanisms of miR-383 in GC function during follicular development remain unknown. In this study, we found that miR-383 was mainly expressed in GC and oocytes of mouse ovarian follicles. Overexpression of miR-383 enhanced estradiol release from GC through targeting RNA binding motif, single stranded interacting protein 1 (RBMS1). miR-383 inhibited RBMS1 by affecting its mRNA stability, which subsequently suppressed the level of c-Myc (a downstream target of RBMS1). Forced expression of RBMS1 or c-Myc attenuated miR-383-mediated steroidogenesis-promoting effects. Knockdown of the transcription factor steroidogenic factor-1 (SF-1) significantly suppressed the expression of Sarcoglycan zeta (SGCZ) (miR-383 host gene), primary and mature miR-383 in GC, indicating that miR-383 was transcriptionally regulated by SF-1. Luciferase and chromatin immunoprecipitation assays revealed that SF-1 specifically bound to the promoter region of SGCZ and directly transactivated miR-383 in parallel with SGCZ. In addition, SF-1 was involved in regulation of miR-383- and RBMS1/c-Myc-mediated estradiol release from GC. These results suggest that miR-383 functions to promote steroidogenesis by targeting RBMS1, at least in part, through inactivation of c-Myc. SF-1 acts as a positive regulator of miR-383 processing and function in GC. Understanding of regulation of miRNA biogenesis and function in estrogen production will potentiate the usefulness of miRNA in the control of reproduction and treatment of some steroid-related disorders.
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