Category Archives: Sertoli Cells

The gonads were embedded in OCT medium (Tissue-Tek, Sakura Finetek, Torrance, CA) and frozen at —70°C. Serial sections of 10-^m thickness were used. After air drying, sections were treated with 1% Triton X-100 in water, rinsed with PBS, and blocked using 1% bovine serum albumin. The sections were then incubated overnight in Sox9 polyclonal antibody diluted 1:500. After washing in PBS, the sections were treated with fluorescein-goat anti-rabbit IgG (Sigma, St. Louis, MO) diluted 1:200 in blocking solution. (more…)

Two microliters of each DNA sample was processed for PCR amplification in a total volume of 20 |xl with 0.25 |xM of each of the following primers: Zfy1, 5'-AAG ATA AGC TTA CAT AAT CAC ATG GA-3'; Zy2, 5'-CCT ATG AAA TCC TTT GCT GCA CAT GT-3' for Zfy; Actin 1, GGG TCA GAA GGA TTC CTA TG; and Actin 2, GGT CTC AAA CAT GAT CTG GG for p-actin used as an internal control. The primers were in 10 mM Tris-HCl pH 8.3, 50 mM KCl, 0.01% gelatin, 2.0 mM MgCl2, 0.2 mM of each dNTP and 1.0 U Taq DNA polymerase. (more…)

Animals All procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals from the Institute for Laboratory Animal Research of the National Academy of Sciences. B6.Ytir mice kept in our colony (backcross generations N 30-35) that possess the B6 genetic background and the Y chromosome from M. musculus domesticus (from Tirano, Italy) were produced as previously described. B6.Ytir males were mated with B6 females, and the day of vaginal plug was taken to be 0.5 days postcoitum (dpc). Bilateral gonads were dissected from embryos at 11.5 up to 18.5 dpc and 30 and 60 days postpartum (dpp). (more…)

The aim of the present study was to correlate the timing and distribution of pre-Sertoli cells that express Sox9 by immunofluorescence with the profile levels of Sox9 transcripts in fetal and postnatal B6-Ytir gonads. It was found that pre-Sertoli cells appear in all undifferentiated B6-Ytir gonads as in wild-type B6 gonads at 11.5-12.5 dpc. From 13.5 dpc onward, however, pre-Sertoli cells expressing the Sox9 protein were absent in about 50% of the gonads. This corresponds to the number of B6-Ytir gonads that develop as ovaries and in the cranial and caudal regions in fetal ovotestis. (more…)

After seminiferous cord formation, Sox9 expression is specific to Sertoli cells, and Sox9 is probably one of the first genes induced by Sry in male gonads. The DNA-binding domains of both Sry and Sox9 proteins are highly conserved and can functionally substitute for each other. A mouse line with a transgene inserted upstream of Sox9 showed that the development of XX males is consistent with Sry being an indirect repressor downstream target of Sox9. Recently, female to male sex-reversal induced by ectopically expressing Sox9 in XX gonads indicated that it can substitute for Sry in the events necessary to form a testis and is likely to act downstream. (more…)

The finding that levels of Sry were lower in sex-reversed B6.Ytir gonads than in non-sex-reversed B6-Ydom strains suggests that low levels and/or mistiming of Sry may cause failure of testis differentiation. However, Lee and Taketo observed that levels of Sry in normal male gonads of the C57BL/6J strain are as low as in the B6-Ytir gonad, suggesting that low levels of Sry transcripts cannot be the sole cause of B6-Ytir sex reversal. Thus the molecular events underlying sex reversal in the B6-Ytir mouse still remain to be elucidated. (more…)

It has been well established that the expression of Sry in undifferentiated gonads of mouse embryos initiates the events leading to testicular differentiation. In some cases of male to female sex reversal, Sry mutations or differing Y alleles can result in differentiation of an ovary instead of a testis. An example occurs in gonads of the strain C57BL/6J (B6) when its Y chromosome is replaced by the Y chromosome (Ydom) of some varieties of Mus musculus domesticus. (more…)