Sex and the single cell. II. There is a time and place for sex.
Sex and the single cell. II. There is a time and place for sex.
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DOI：
10.1371/journal.pbio.1000365
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发表时间：
2010-05-04
期刊：
影响因子：
9.8
通讯作者：
Baker BS
中科院分区：
文献类型：
--
作者：
Robinett CC;Vaughan AG;Knapp JM;Baker BS
在雄性和雌性果蝇中，只有一部分细胞具有性分化的潜力，使得雄性和雌性果蝇都是性分化和性未分化细胞的镶嵌体。果蝇性别等级通过等级中的末端基因、双性（dsx）和无果（fru）的活动控制体细胞的性分化。我们将 GAL4 插入到 dsx 基因中，从而使我们能够可视化两性中表达 dsx 的细胞。在发育过程中和成年后，我们发现 XX 和 XY 个体都是表达 dsx 和/或无果 (fruM) 的细胞和组织的精细镶嵌体，因此具有性别分化的潜力，而那些则没有。进化论表明，这种马赛克式的性表达很可能是其他具有两种性别的动物物种的特性。这些结果也导致我们对果蝇的性别等级如何调节性别特异性功能的观点进行了重大修正。并不是存在一个单一的调控事件来控制所有下游性别决定调控基因的活动——在雌性中开启性致死（Sxl）RNA剪接活性，而在雄性中关闭它——此外，还有对末端调控基因dsx和fru表达的复杂的时间和空间转录控制。因此，性发育的组织特异性方面是由 Sxl 的转录后控制以及 dsx 和 fru 表达的转录控制共同指定的。从形态上来说，果蝇要么是雄性，要么是雌性。性别的确定是一个多步骤的过程，取决于受精卵是只有一条 X 染色体（将发育为男性）还是两条 X 染色体（将发育为女性）。这种对性别的初步评估激活了一系列调控基因，最终导致双性基因（dsx）编码的蛋白质的雄性或雌性版本的表达。这些来自 dsx 基因的性别特异性蛋白指导着躯体性发育的大部分方面，包括明显区分男性和女性的所有第二性征的发育。在果蝇中，与大多数动物物种一样，只有某些组织在两种性别之间存在明显差异，因此我们提出了一个问题：动物中的所有细胞是否都知道它们的性别。也就是说，所有细胞都表达 dsx 吗？我们开发了一种遗传工具，可以让我们可视化表达 dsx 的细胞。引人注目的是，dsx 仅在一部分组织中表达。因此，两种性别的成年果蝇似乎都是由知道自己性别的细胞和不知道自己性别的细胞组成的镶嵌体。
In both male and female Drosophila, only a subset of cells have the potential to sexually differentiate, making both males and females mosaics of sexually differentiated and sexually undifferentiated cells. The Drosophila melanogaster sex hierarchy controls sexual differentiation of somatic cells via the activities of the terminal genes in the hierarchy, doublesex (dsx) and fruitless (fru). We have targeted an insertion of GAL4 into the dsx gene, allowing us to visualize dsx-expressing cells in both sexes. Developmentally and as adults, we find that both XX and XY individuals are fine mosaics of cells and tissues that express dsx and/or fruitless (fruM), and hence have the potential to sexually differentiate, and those that don't. Evolutionary considerations suggest such a mosaic expression of sexuality is likely to be a property of other animal species having two sexes. These results have also led to a major revision of our view of how sex-specific functions are regulated by the sex hierarchy in flies. Rather than there being a single regulatory event that governs the activities of all downstream sex determination regulatory genes—turning on Sex lethal (Sxl) RNA splicing activity in females while leaving it turned off in males—there are, in addition, elaborate temporal and spatial transcriptional controls on the expression of the terminal regulatory genes, dsx and fru. Thus tissue-specific aspects of sexual development are jointly specified by post-transcriptional control by Sxl and by the transcriptional controls of dsx and fru expression. Morphologically, fruit flies are either male or female. The specification of sex is a multi-step process that depends on whether the fertilized egg has only one X chromosome (will develop as male) or two X chromosomes (will develop as female). This initial assessment of sex activates a cascade of regulatory genes that ultimately results in expression of either the male or female version of the protein encoded by the doublesex gene (dsx). These sex-specific proteins from the dsx gene direct most aspects of somatic sexual development, including the development of all of the secondary sexual characteristics that visibly distinguish males and females. In flies, as in most animal species, only some tissues are obviously different between the two sexes, so we asked the question of whether all cells in the animal nevertheless know which sex they are. That is, do all cells express dsx? We have developed a genetic tool that lets us visualize the cells in which the dsx is expressed. Strikingly, dsx is only expressed in a subset of tissues. Thus, adult flies of both sexes appear to be mosaics of cells that do know their sex and cells that do not know their sex.
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影响因子：
2.7
作者：
CHAPMAN, KB;WOLFNER, MF
通讯作者：
WOLFNER, MF
影响因子：
10.5
作者：
BOPP, D;BELL, LR;SCHEDL, P
通讯作者：
SCHEDL, P
DOI：
10.1073/pnas.0535280100
发表时间：
2003-03-04
影响因子：
11.1
作者：
Gong, WJ;Golic, KG
通讯作者：
Golic, KG
影响因子：
4
作者：
Bashaw, GJ;Baker, BS
通讯作者：
Baker, BS
影响因子：
56.9
作者：
Ferveur, JF;Savarit, F;Jallon, JM
通讯作者：
Jallon, JM