FETAL GENE EXPRESSION IN MOUSE SEX DETERMINATION

这个项目的目标是剖析 通过鉴定新基因确定/分化小鼠途径 在这条途径中，确定它们如何影响每一个 其他，并确定其产品的功能。以来 睾丸决定因子基因Sry的发现， 了解了它调节哪些其他基因来激活睾丸 分化或抑制卵巢分化，因此， 分化途径仍然是一个谜。我们因此 我建议通过比较mRNA来寻找这个途径中的新基因 在正常XY男性胎儿的生殖嵴中表达，正常XX 女性和XY胎儿注定要被逆转性别。鼠标 菌株C57 BL/6 JEi-Y-pos（B6 Ypos）将用于产生XY性别 反转的胎儿这些小鼠携带来自小鼠的Y染色体 在C57 BL/6 J（B6）遗传背景下， 雌雄同体或雌性的后代（从不正常 男性）。此外，用小鼠挽救性逆转表型， musculus Sry转基因已经证明Y染色体- 导致性逆转的相关决定因素是睾丸决定因素， 因子基因Sry。11.5和12.5天后生殖嵴的RNA CO2（d.p.c.）来自XX和XY B6小鼠以及来自XX和XY B6 YPOS小鼠 将使用增强差异显示（EDD）进行比较。 在这个 目前，已鉴定出5种候选mRNA。信使rna 确定为处于性别决定/分化途径 因为它们表现出男性和女性之间的表达差异， XY性别反转的生殖嵴将被追求，以建立他们的角色 在通道中。一些新发现的基因的功能将 通过使用ES细胞将无效等位基因引入小鼠中来直接测试 基因打靶技术和确定对性别表型的影响。 携带性别决定途径基因无效等位基因的小鼠将被 用于确定途径中的一个基因如何通过以下方式影响其他基因： 分析纯合无效生殖嵴的RNA的表达， 性别决定途径mRNA。很可能纯合突变体 这些基因中的一些将产生部分性逆转表型（如 在一些XY B6 Ypos小鼠中可见）。在这些情况下， 携带一个以上性别决定无效等位基因的组合 为了建立这些基因的功能关系， 通路

The goals of this project are to dissect the sex determination/differentiation pathway of mice by identifying new genes in this pathway, establishing how they influence the expression of each other, and by determining the functions of their products. Since the discovery of the testis-determining factor gene Sry, little has been learned about which other genes it regulates to activate testis differentiation or repress ovarian differentiation, and thus this pathway of differentiation still remains largely a mystery. We thus propose to search for new genes in this pathway by comparing mRNAs expressed in genital ridges from fetuses of normal XY males, normal XX females and XY fetuses that are destined to be sex reversed. The mouse strain C57BL/6JEi-Y-pos(B6Ypos) will be used to generate XY sex reversed fetuses. These mice carry the Y chromosome from Mus poschiavinus on the C57BL/6J(B6) genetic background and produce XY offspring that are either hermaphrodites or females (never normal males). Furthermore, rescue of the sex reversal phenotype with a Mus musculus Sry transgene has demonstrated that the Y-chromosome- associated determinant causing sex reversal is the testis-determining factor gene Sry. RNAs from genital ridges at 11.5 and 12.5 days post coitum (d.p.c.) from XX and XY B6 mice and from XX and XY B6YPOS mice will be compared using enhanced differential display (EDD). At this time, five candidate mRNAs have been identified. Messenger RNAs identified as being in the sex determination/differentiation pathway because they show differences in expression between male and female and XY sex reversed genital ridges will be pursued to establish their roles in the pathway. The function of some of the newly identified genes will be tested directly by introducing null alleles into mice using ES cell gene targeting technology and determining the effect on sex phenotype. Mice carrying null alleles of sex determination pathway genes will be used to determine how one gene in the pathway influences others by assaying RNA of homozygous null genital ridges for expression of other sex determination pathway mRNAs. It is likely that homozygous mutants of some of these genes will produce partial sex reversal phenotypes (as seen in some of the XY B6Ypos mice). In these cases mice will be bred that carry combinations of more than one sex determination null allele to establish the functional relationships of these genes in the pathway.