Tissue-specific patterns of microRNA (miRNA) expression contribute to organogenesis during embryonic development. Using the embryonic chicken gonads as a model for vertebrate gonadogenesis, we previously reported that miRNAs are expressed in a sexually dimorphic manner during gonadal sex differentiation. Being male biased, we hypothesised that up-regulation of microRNA 202* (MIR202*) is characteristic of testicular differentiation. To address this hypothesis, we used estrogen modulation to induce gonadal sex reversal in embryonic chicken gonads and analyzed changes in MIR202* expression. In ovo injection of estradiol-17beta at Embryonic Day 4.5 (E4.5) caused feminization of male gonads at E9.5 and reduced MIR202* expression to female levels. Female gonads treated at E3.5 with an aromatase inhibitor, which blocks estrogen synthesis, were masculinized by E9.5, and MIR202* expression was increased. Reduced MIR202* expression correlated with reduced expression of the testis-associated genes DMRT1 and SOX9, and up-regulation of ovary-associated genes FOXL2 and CYP19A1 (aromatase). Increased MIR202* expression correlated with down-regulation of FOXL2 and aromatase and up-regulation of DMRT1 and SOX9. These results confirm that up-regulation of MIR202* coincides with testicular differentiation in embryonic chicken gonads.
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9 March 2011
Manipulation of Estrogen Synthesis Alters MIR202* Expression in Embryonic Chicken Gonads
Stephanie C. Bannister,
Craig A. Smith,
Kelly N. Roeszler,
Timothy J. Doran,
Andrew H. Sinclair,
Mark L.V. Tizard
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Biology of Reproduction
Vol. 85 • No. 1
July 2011
Vol. 85 • No. 1
July 2011
aromatase inhibitor
chicken embryo
E2
estradiol/estradiol receptor
Estradiol-17β
estrogen
gonad