PRIMARY SEX DETERMINATION AND FERTILITY IN MAMMALS

描述：(改编自申请人的摘要)插入酪氨酸酶 微型基因导致小鼠Sox9上游的一个小片段缺失(&lt；200kb) 11号染色体。该突变(Ods)与双等位基因表达有关 Sox9与XX胎儿性腺的睾丸发育建议进行的研究是 检验一种假设，即消耗臭氧层物质突变含有一种远距离性腺特异的基因 通常介导抑制Sox9表达的调控元件 XX胎儿性腺。据预测，Sox9是导致 支持细胞分化，睾丸发育中的关键事件，以及 可能是Sry的直接下游目标，主要是决定睾丸的 Y染色体上的基因。 第一个具体目标是在XY ES细胞中重新创建消耗臭氧层物质缺失并生成 新的突变小鼠品系。这一方法将证明突变表型 是由删除引起的，并能缩短删除，从而使抑制子 绑定元素可以更精确地本地化。一旦删除 最小化，它在人类中的同源区域将被识别和测试，如果 该区域的突变与散发性和家族性白血病有关。 XX(Y-)男性。 第二个具体目标是确定染色体的数量和位置 常染色体和/或X连锁基因与ODS性逆转有关。参与其中 常染色体/X连锁基因的可能性已经通过观察到的ODS性 反转在FVB背景中是完全穿透的，而只有10% A/J背景中的渗透者。显性的A/J等位基因将通过 AFVF1杂交F2代突变表型的表达 消耗臭氧层物质/+小鼠。Dax1和Dax1等已知候选性别决定基因的作用 此外，SOX3还将在该系统中进行评估。 第三个具体目标是检查Y染色体基因表达的作用 在精子发生中，利用了ODS性逆转的优势。雄鼠缺乏 将产生包含所有其他Y染色体基因(=XY ods/+)的SRY 并将检查它们的生育能力和精子生成情况。来测试一下 Y染色体基因在睾丸体细胞中的表达是必要的 对于精子发生，正常的精原干细胞携带LacZ 报告基因将被移植到成年XX ODS/+睾丸中。The XY 非转基因男性将注射白消安，这将阻止 精子发生，并作为对照受体。

DESCRIPTION: (Adapted from the applicant's abstract) Insertion of tyrosinase minigene resulted in a small deletion (<200 kb) upstream of Sox9 on the mouse chromosome 11. This mutation (Ods) is associated with biallelic expression of Sox9 and development of testes in the XX fetal gonad. The proposed study is to test the hypothesis that Ods mutation harbors a long-range gonad-specific regulatory element that normally mediates the repression of Sox9 expression in the XX fetal gonad. It was predicted that Sox9 is the primary inducer of Sertoli cell differentiation, the key event in testis development, and possibly, a direct downstream target of Sry, the primary testis-determining gene on the Y chromosome. The first specific aim is to recreate Ods deletions in XY ES cells and generate new lines of mutant mice. This approach will prove that the mutation phenotype is caused by deletion and enable to shorten the deletion, so that the repressor binding elements can be more precisely localized. Once the deletion is minimized, its homologous region in the human will be identified and tested if mutations in this region are associated with sporadic and familial cases of XX(Y-) males. The second specific aim is to determine the number and chromosomal location of autosomal and/or X-linked genes involved in Ods sex reversal. The involvement of autosomal/X-linked genes has been suggested by the observation that Ods sex reversal is fully penetrant in the FVB background while only 10 percent penetrant in the A/J background. The dominant A/J allele will be identified by expression of the mutant phenotype in the F2 offspring from the cross of AFVF1 Ods/+ mice. The role of known candidate sex determining genes such as Dax1 and Sox3 will be, in addition, assessed in this system. The third specific aim is to examine the role of Y chromosome gene expression in spermatogenesis, taking the advantage of Ods sex-reversal. Male mice lacking Sry but containing all other Y chromosome genes (= XY Ods/+) will be produced and their fertility and spermatogenesis will be examined. To test whether expression of Y chromosome genes in somatic cells of the testis is necessary for spermatogenesis, normal spermatogonial stem cells carrying the lacZ reporter gene will be transplanted into adult XX Ods/+ testes. The XY non-transgenic male will be injected with busulfan, which blocks spermatogenesis, and serve as a control recipient.