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Aromatase inhibition reduces expression of FOXL2 in the embryonic chicken ovary
Author(s) -
Hudson Quanah J.,
Smith Craig A.,
Sinclair Andrew H.
Publication year - 2005
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.20388
Subject(s) - aromatase , biology , ovary , estrogen , medicine , endocrinology , embryonic stem cell , colocalization , aromatase inhibitor , sexual differentiation , gene , microbiology and biotechnology , genetics , cancer , breast cancer
P450‐aromatase is the terminal estrogen‐synthesizing enzyme and a key gene in avian sex determination. Aromatase is expressed specifically in female gonads, but not male gonads, at the onset of sexual differentiation. This enzyme shows temporal and spatial colocalization with the forkhead transcription factor FOXL2 in the embryonic chicken ovary, suggesting a causal link. Mutations in FOXL2 are associated with premature ovarian failure in humans. Foxl2 null mice also present with premature ovarian failure. Here, we show that FOXL2 expression is reduced but not abolished in chicken embryos subjected to experimental female to male sex‐reversal with an aromatase inhibitor. This finding suggests that FOXL2 lies upstream of aromatase in avian sex determination, but that it responds to depleted estrogen synthesis. The reduction in FOXL2 expression may be accounted for by interruption of a positive feedback loop by means of estrogen, or the influence of testis promoting factors such as SOX9 and DMRT1 in the masculinized gonads. Developmental Dynamics 233:1052–1055, 2005. © 2005 Wiley‐Liss, Inc.