Developmental appearance of proteins identified by two-dimensional gel electrophoresis in mouse gonadal tissue.

Gonadal protein patterns of the mouse were studied during fetal development by two-dimensional gel electrophoresis. Fetal mice at days 8.5, 10.5, 12.5, and 14.5 post-coitum were analyzed for male or female specific proteins. Although no sex specific proteins were found, several proteins were found which were expressed in significantly different amounts in the two sexes at about the time of gonadal differentiation. Hence, quantitative differences, rather than qualitative ones, could be related to the initiation of testis or ovary development.

Sex vesicle "entrapment": translocation or nonhomologous recombination of misaligned Yp and Xp as alternative mechanisms for abnormal inheritance of the sex-determining region.

Abnormal inheritance of the sex determining region, normally located on Yp, results in about 1 in 20,000 phenotypic males with a 46,XX genotype. Studies to date indicate that many 46,XX males apparently arise due to a balanced, yet abnormal, nonhomologous interchange of Xp and Yp termini. However, 2 of the 5 XX males we report here have 3 copies of the pseudoautosomal locus, MIC2. Thus, they appear to have inherited the sex determining region as a result of Yp sequences being added onto the X pseudoautosomal region. Such an unequal, extremely nonhomologous interchange could alternatively be considered to arise from an unbalanced translocation of Yp to Xp. Our results suggest that very unequal interchange or translocation of Yp sequences onto the X pseudoautosomal region is not as rare a mechanism for XX males as originally thought. We also suggest that sex vesicle "entrapment" favors the association of a Yp fragment to the X pseudoautosomal region over a translocation to either Xq or an autosome.

Northern analyses using single-stranded probes do not support a role for GATA/GACA repeats in sex determination in mice and men.

The possible role of GATA/GACA repeated sequences in mammalian sex determination was investigated using Northern analyses of mouse and human RNA. Brain, liver, and gonadal RNA from three developmental stages of mice of both sexes and also human fetal RNA from various tissues were hybridized to both sense and antisense Bkm riboprobes as well as to the synthetic oligonucleotide (GATA)5. At low levels of stringency, putative transcripts of various sizes were observed in all tissue samples with all probes. At high stringency, only a putative transcript of approximately 12 kb was observed, but this was later shown to consist of contaminating DNA. No sex-specific differences were observed in any tissue or developmental stage. Thus, we find no evidence that the GATA/GACA repeated sequences are specifically expressed in quantities detectable by Northern analyses in a manner important to mammalian sex determination.

Characterization of GATA/GACA-related sequences on proximal chromosome 17 of the mouse.

Autosomal loci have long been thought to have a role in sex determination of mice. We studied the localization of GATA/GACA repeats on chromosome 17 in regard to the possibility of their involvement in sex determination. We performed in situ hybridizations on chromosome 17s carrying the Hairpain tail (Thp) deletion of the T locus since this deletion has been associated with sex reversal and hermaphroditism. We did not detect a significant decrease in the amount of hybridization of GATA/GACA repeats to the Thp deletion. In addition, three Bkm-positive cosmids from proximal chromosome 17 did not contain sequences deleted in Thp or TOrl and a fetal testes cDNA probe did not hybridize to the cosmid sequences. Although we confirmed the localization of Bkm-related sequences on chromosome 17, we were not able to relate GATA/GACA sequences on chromosome 17 to sex determination in mice.

Sex determination in mice: Y and chromosome 17 interactions.

Mice provide material for studies of Y-chromosomal and autosomal sequences involved in sex determination. Eicher and coworkers have identified four subregions in the mouse Y chromosome, one of which corresponds to the Sxr fragment. This fragment demonstrates that only a small portion of the Y is necessary for male sex determination. The mouse Y chromosome also shows variants: the BALB/cWt Y chromosome, which causes nondisjunction of the Y in some germ cells leading to XO and XYY cells and resulting in many infertile true hermaphrodites; the YDom, a wild-type chromosome which can result in sex reversal on a C57BL/6J background; and Y-chromosomal variants detected with Y-derived genomic DNA clones among inbred strains. Two different autosomal loci affecting sex differentiation have been identified in the mouse by Eicher and coworkers. The first of these has not been mapped to a particular chromosome and has been designated Tda-1 (Testis-determining autosomal-1). This is the locus in C57BL/6J mice at which animals must be homozygous in order to develop as true hermaphrodites or sex-reversed animals in the presence of YDom. The other locus has been identified on proximal chromosome 17. This locus also caused hermaphrodites on the C57BL/6J background and it is most easily interpreted as a locus deleted in Thp. It is located in a region on chromosome 17 containing other genes or DNA sequences that may be related to sex determination. These include both the Hye (histocompatibility Y expression) locus that affects the amount of male-specific antigen detected by serological and cell-mediated assays and a concentration of Bkm sequences.(ABSTRACT TRUNCATED AT 250 WORDS)