Analysis of the testes of H-Y negative XOSxrb mice suggests that the spermatogenesis gene (Spy) acts during the differentiation of the A spermatogonia.
H-Y antigen negative XOSxrb mice, like their H-Y positive XOSxra counterparts, have testes; but, in contrast to XOSxra males, XOSxrb testes almost totally lack meiotic and postmeiotic stages of spermatogenesis. The quantitative analysis of the testes of XOSxrb males and their XY +/- Sxrb sibs, described in the present study, identified two distinct steps in this spermatogenic failure. First, there was a reduction in mitotic activity among T1 prospermatogonia, so that approximately half the normal number of T2 prospermatogonia were produced. Second, there was a dramatic decrease in the number of A3 and A4 spermatogonia and no Intermediate or B spermatogonia. These reductions were also largely due to decreased mitotic activity, there being a shortage of A1 and A2 spermatogonial divisions and no divisions among A3 or A4 spermatogonia. Mitotic activity among the T2 prospermatogonia and the undifferentiated A spermatogonia was normal. This means that the spermatogonial stem cells, which are a subset of the undifferentiated A spermatogonia, are unaffected in XOSxrb mice. Sxrb is now known to have arisen by deletion of DNA from Sxra. It is clear from the present findings that a gene (or genes) present in the deleted DNA plays a major role in the survival and proliferation of the differentiating A spermatogonia.
Sutcliffe
M J
MJ
MRC Mammalian Development Unit, London, UK.
Burgoyne
P S
PS
D000818:Animals; D001835:Body Weight / Q000235:genetics; D015870:Gene Expression; D006182:H-Y Antigen / Q000276:immunology*; D008297:Male; D051379:Mice; D008940:Mitotic Index; D009929:Organ Size; D012732:Sex Determination Analysis; D013091:Spermatogenesis / Q000235:genetics*; D013093:Spermatogonia / Q000254:growth & development*; D013094:Spermatozoa / Q000254:growth & development*; D013737:Testis / Q000033:anatomy & histology / Q000196:embryology*
D006182:H-Y Antigen