Low levels of Sry transcripts cannot be the sole cause of B6‐YTIR sex reversal

CH Lee, T Taketo - Genesis, 2001 - Wiley Online Library
CH Lee, T Taketo
Genesis, 2001Wiley Online Library
Sry, a single‐copy gene on the Y‐chromosome, triggers the fetal gonad to begin testis
differentiation in mammals. On the other hand, mutation or absence of Sry results in ovary
differentiation and the female phenotype. However, cases of XY sex reversal in the presence
of wild‐type Sry exist in mice and man. One such example is the B6‐YTIR mouse, whose
autosomes and X‐chromosome are from the C57BL/6J mouse (an inbred strain of Mus
musculus molossinus), whereas the Y‐chromosome is from a Mus musculus domesticus …
Abstract
Summary: Sry, a single‐copy gene on the Y‐chromosome, triggers the fetal gonad to begin testis differentiation in mammals. On the other hand, mutation or absence of Sry results in ovary differentiation and the female phenotype. However, cases of XY sex reversal in the presence of wild‐type Sry exist in mice and man. One such example is the B6‐YTIR mouse, whose autosomes and X‐chromosome are from the C57BL/6J mouse (an inbred strain of Mus musculus molossinus), whereas the Y‐chromosome is from a Mus musculus domesticus mouse originating in Tirano, Italy. The B6‐YTIR mouse never develops normal testes and instead develops ovaries or ovotestes in fetal life. It has been suggested that low levels of Sry transcription may account for the aberrant testis differentiation in the B6‐YTIR mouse. In this study, however, we observed relatively low levels of Sry transcripts not only in B6‐YTIR but also in B6 mice, which develop normal testes. We conclude that low dosage of Sry transcripts cannot be the sole cause of sex reversal in the B6‐YTIR gonad. genesis 30:7–11, 2001. © 2001 Wiley‐Liss, Inc.
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