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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mammalian sex determination is the genetic process that commits the undifferentiated bipotential gonads to develop as either testes or ovaries. The differentiation of SOX9-expressing Sertoli cells is assumed to be necessary to initiate testis development. Insectivorous moles of the genus Talpa represent a unique case of generalized true hermaphroditism, as XX female moles constitutively develop two ovotestes instead of normal ovaries. In this work, we have investigated the expression patterns of a number of genes known to play key roles in gonad organogenesis, throughout the entire process of ovotestis development in female moles. Molecular and morphological evidence are provided that these ovotestes contain primary medullary testis-like cords, Leydig cells, peritubular myoid cells, and a testis-specific vasculature, but no Sertoli cells. Our results show for the first time that SOX9 is not required for the formation of the primary testis cords, but it is necessary for the maintenance and subsequent development of these cords. In addition, the expression pattern of WNT4 in male and female moles indicates that this gene inhibits Leydig cell differentiation and, contrary to the proposed scenario in the mouse, it is not required for the colonization and survival of primordial germ cells. According to our data, mole ovotestes result from a process of PDGFRalpha-mediated mesonephric cell migration, which occurs simultaneously in both sexes. The fact that FST remains inactive during the critical stages of female gonad development, explains the lack of migration inhibition, and may be a consequence of improper WNT4 signalling in the mole.
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PMID:SOX9 is not required for the cellular events of testicular organogenesis in XX mole ovotestes. 1938 59

Some cellular events are crucial in testis organogenesis, including Sertoli and Leydig cell differentiation, mesonephric cell migration and testis cord formation. These processes are controlled by transcription factors, paracrine signalling and hormones. Using the mole species Talpa occidentalis as an alternative animal model, we report the expression patterns of nine genes during testis differentiation and analyse their implications in the above-mentioned cellular processes. We show that: 1) Sertoli cell differentiation occurs very early and precedes mesonephric cell migration, indicating that the latter is not needed for the endocrine cytodifferentiation of Sertoli cells; 2) the time of Leydig cell differentiation is consistent with the participation of PDGFR-alpha in promoting the migration and/or proliferation of Leydig cell precursors, and with that of WNT4 signalling in inhibiting Leydig cell differentiation and 3) the formation of the tunica albuginea involves intragonadal cell migration/movement. These results demonstrate that testicular organogenesis in the mole differs from that in the mouse in some particular aspects, thus providing evidence that the spatio-temporal pattern of testis development is not highly conserved during mammalian evolution.
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PMID:The spatio-temporal pattern of testis organogenesis in mammals - insights from the mole. 1959 20