Jim Beaux
01-14-2010, 10:39 PM
I'll cover plain English in a moment, but for those intrested in SCIENTIFICALESE, here is the sci-jargon from the journal "Cell".
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In mammals, the transcription factor SRY, encoded by the Y chromosome, is normally responsible for triggering the indifferent gonads to develop as testes rather than ovaries. However, testis differentiation can occur in its absence. Here we demonstrate in the mouse that a single factor, the forkhead transcriptional regulator FOXL2, is required to prevent transdifferentiation of an adult ovary to a testis. Inducible deletion of Foxl2 in adult ovarian follicles leads to immediate upregulation of testis-specific genes including the critical SRY target gene Sox9. Concordantly, reprogramming of granulosa and theca cell lineages into Sertoli-like and Leydig-like cell lineages occurs with testosterone levels comparable to those of normal XY male littermates. Our results show that maintenance of the ovarian phenotype is an active process throughout life. They might also have important medical implications for the understanding and treatment of some disorders of sexual development in children and premature menopause in women.For a video summary of this article, see the PaperFlick file with the Supplemental Data available online.
URL http://http://www.cell.com/abstract/S0092-8674(09)01433-0
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And now simplified in plain English.
This study was done in mice but the scientists are fairly sure the results apply to humans.
A process before birth makes us 'male' or 'female'
BUT there is a lifelong process, involving Foxl2, that controls whether we switch gender. In this particular case, it happens to be female ovaries switching to male testicles.
In brief, it isn't just about what happens before we are born. There are genetics playing about during our whole lifetime to 'decide' which side of the fence we sit.
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In mammals, the transcription factor SRY, encoded by the Y chromosome, is normally responsible for triggering the indifferent gonads to develop as testes rather than ovaries. However, testis differentiation can occur in its absence. Here we demonstrate in the mouse that a single factor, the forkhead transcriptional regulator FOXL2, is required to prevent transdifferentiation of an adult ovary to a testis. Inducible deletion of Foxl2 in adult ovarian follicles leads to immediate upregulation of testis-specific genes including the critical SRY target gene Sox9. Concordantly, reprogramming of granulosa and theca cell lineages into Sertoli-like and Leydig-like cell lineages occurs with testosterone levels comparable to those of normal XY male littermates. Our results show that maintenance of the ovarian phenotype is an active process throughout life. They might also have important medical implications for the understanding and treatment of some disorders of sexual development in children and premature menopause in women.For a video summary of this article, see the PaperFlick file with the Supplemental Data available online.
URL http://http://www.cell.com/abstract/S0092-8674(09)01433-0
*****************
And now simplified in plain English.
This study was done in mice but the scientists are fairly sure the results apply to humans.
A process before birth makes us 'male' or 'female'
BUT there is a lifelong process, involving Foxl2, that controls whether we switch gender. In this particular case, it happens to be female ovaries switching to male testicles.
In brief, it isn't just about what happens before we are born. There are genetics playing about during our whole lifetime to 'decide' which side of the fence we sit.