Y chromosome short arm-Sxr recombination in XSxr/Y males causes deletion of Rbm and XY female sex reversal.

Abstract

We earlier described three lines of sexreversed XY female mice deleted for sequences believed close to the testes-determining gene (Sry) The mouse mutation sex reversed (Sxr) arose through a duplication of the Y chromosome short arm (Yp), including the sex-determining gene Sry and transposition to the pseudoautosomal region at the end of the Y long arm (1-3). In addition to Sry, Sxr contains all of the Y chromosome genes necessary for spermatogenesis up to the round spermatid stage (4) and all other known Yp genes including Zfyl, Zfy2, Ubelyl, and Smcy (5). Pseudoautosomal crossing-over in carrier (X/ YSxr) males transfers Sxr to the X chromosome, causing sex reversal of the X/XSxr progeny (6).Normally Sxr is transmitted only through X/YSxr males, as X/XSxr males are sterile. However, a nonrandom X-inactivation pattern can be brought about in X/XSxr animals using the T16H translocation [T(X;16)16H]. In some X(T16H)/XSxr individuals the Sxr region is inactivated with the result that female development occurs (7,8 10403The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

An analysis of meiotic impairment and of sex chromosome associations throughout meiosis in XYY mice

“…Nevertheless, where two regions of homologous synapsis are achieved (PAR-PAR synapsis and presumed Yp-Yp synapsis), two chiasma can form, as evidenced by the maintenance of "X-Y-Y" chains through to diakinesis/MI. This potential for chiasma formation in regions of the Y that are normally excluded from recombination is also seen in XSxr a Y males (Laval et al, 1995), and it puts into question the hypothesis of McKee and Handel (1993), that the non-PAR axes of the X and Y are somehow protected from doublestrand breaks and recombination by being sequestered in the "sex body." It is interesting that among our present estimates of diakinesis/MI ratios for XY -y configurations, chain trivalents had a lower ratio (1.31), than any of the configurations that included a univalent.…”

Switching on sex: transcriptional regulation of the testis-determining geneSry

“…Large deletions of the Y chromosome, estimated to be 3-4 Mb in size (Mahadevaiah et al, 1998), also cause sex reversal in mice, but in this case the deletions are further away from the gene and are thought to act through a generalised position effect, bringing Sry closer to a heterochromatic region that prevents its expression (Capel et al, 1993b;Laval et al, 1995). They are, therefore, not instructive in locating potentially important regulatory intervals.…”

Of sex and determination: marking 25 years of Randy, the sex-reversed mouse

“…The Goodfellow group cut this region into small fragments and tested each on Southern blots containing male and female DNA from human, mice and cattle. Only one human Y-fragment was identified that showed male-specific bands in human and several other mammalian genomes , as well as in XY and XX male mice [where the latter carried a small region of the Y chromosome short arm termed Sxr(b) (Laval et al, 1995)], but not XX or XY Tdym1 female mice (Gubbay et al, 1990). As unique sequences conserved between the Y chromosomes of different mammalian species are very rare, these results implied that this human Y chromosome fragment probably contained TDF/Tdy.…”