Male-specific cell migration into the developing gonad.
BACKGROUND
The gene Sry acts as a developmental switch, initiating a pathway of gene activity that leads to the differentiation of testis rather than ovary from the indifferent gonad (genital ridge) in mammalian embryos. The early events following Sry expression include rapid changes in the topographical organization of cells in the XY gonad. To investigate the contribution of mesonephric cells to this process, gonads from wild-type mice (CD1), and mesonephroi from a transgenic strain ubiquitously expressing beta-galactosidase (ROSA26), were grafted together in vitro. After culture, organs were fixed and stained for beta-galactosidase activity to identify cells contributed from the mesonephros to the male or female gonad.


RESULTS
Migration of mesonephric cells occurred into XY but not XX gonads from 11.5-16.5 days post coitum (dpc). Somatic cells contributed from the mesonephros were distinguished by their histological location and by available cell-specific markers. Some of the migrating cells were endothelial; a second population occupied positions circumscribing areas of condensing Sertoli cells; and a third population lay in close apposition to endothelial cells.


CONCLUSIONS
OFFgration from the mesonephros to the gonad is male specific at this stage of development and depends on an active signal that requires the presence of a Y chromosome in the gonad. The signals that trigger migration operate over considerable distances and behave as chemoattractants. We suggest that migration of cells into the bipotential gonad may have a critical role in initiating the divergence of development towards the testis pathway.
Martineau
J
J
Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Nordqvist
K
K
Tilmann
C
C
Lovell-Badge
R
R
Capel
B
B
D000818:Animals; D002455:Cell Division; D002465:Cell Movement; D002630:Chemotactic Factors / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D006066:Gonads / Q000166:cytology / Q000196:embryology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins; D009924:Organ Culture Techniques; D012727:Sex Characteristics; D051876:Sex-Determining Region Y Protein; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors
D002630:Chemotactic Factors; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D051876:Sex-Determining Region Y Protein; C497746:Sry protein, mouse; D014157:Transcription Factors