Thevenet Laurie, Albrecht Kenneth H, Malki Safia, Berta Philippe, Boizet-Bonhoure Brigitte, Poulat Francis
Institut de Génétique Humaine CNRS UPR1142, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France.
J Biol Chem. 2005 Nov 18;280(46):38625-30. doi: 10.1074/jbc.M504127200. Epub 2005 Sep 15.
In mammals, male sex determination is controlled by the SRY protein, which drives differentiation of the bipotential embryonic gonads into testes by activating the Sertoli cell differentiation program. The morphological effects of SRY are well documented; however, its molecular mechanism of action remains unknown. Moreover, SRY proteins display high sequence variability among mammalian species, which makes protein motifs difficult to delineate. We previously isolated SIP-1/NHERF2 as a human SRY-interacting protein. SIP-1/NHERF2, a PDZ protein, interacts with the C-terminal extremity of the human SRY protein. Here we showed that the interaction of SIP-1/NHERF2 and SRY via the SIP-1/NHERF2 PDZ1 domain is conserved in mice. However, the interaction occurs via a domain that is internal to the mouse SRY protein and involves a different recognition mechanism than human SRY. Furthermore, we show that mouse and human SRY induce nuclear accumulation of the SIP-1/NHERF2 protein in cultured cells. Finally, a transgenic mouse line expressing green fluorescent protein under the control of the mouse Sry promoter allowed us to show that SRY and SIP-1/NHERF2 are co-expressed in the nucleus of pre-Sertoli cells during testis determination. Taken together, our results suggested that the function of SIP-1/NHERF2 as an SRY cofactor during testis determination is conserved between human and mouse.
在哺乳动物中，雄性性别决定由SRY蛋白控制，该蛋白通过激活支持细胞分化程序，驱动双潜能胚胎性腺分化为睾丸。SRY的形态学效应已有充分记载；然而，其分子作用机制仍不清楚。此外，SRY蛋白在哺乳动物物种间表现出高度的序列变异性，这使得蛋白质基序难以描绘。我们之前分离出SIP-1/NHERF2作为一种与人类SRY相互作用的蛋白。SIP-1/NHERF2是一种PDZ蛋白，与人类SRY蛋白的C末端相互作用。在此我们表明，SIP-1/NHERF2与SRY通过SIP-1/NHERF2的PDZ1结构域的相互作用在小鼠中是保守的。然而，这种相互作用是通过小鼠SRY蛋白内部的一个结构域发生的，并且涉及一种与人类SRY不同的识别机制。此外，我们表明小鼠和人类SRY在培养细胞中诱导SIP-1/NHERF2蛋白的核积累。最后，一个在小鼠Sry启动子控制下表达绿色荧光蛋白的转基因小鼠品系使我们能够证明，在睾丸决定过程中，SRY和SIP-1/NHERF2在支持前体细胞的细胞核中共表达。综上所述，我们的结果表明，SIP-1/NHERF2作为睾丸决定过程中SRY辅因子的功能在人和小鼠之间是保守的。
