Read D, Manley J L
Department of Biological Sciences, Columbia University, New York, NY 10027.
EMBO J. 1992 Mar;11(3):1035-44. doi: 10.1002/j.1460-2075.1992.tb05142.x.
A protein present in nuclear extracts of Drosophila embryos binds multiple sites in the promoter and genetically defined autoregulatory element of the pair-rule gene even-skipped (eve). We reported here the isolation of a cDNA encoding this binding activity, the sequence of which identifies it as the 69 kDa zinc finger tramtrack (ttk) protein. As ttk was previously implicated in controlling the expression of another pair-rule gene, fushi tarazu (ftz), our findings suggest that ttk plays a role in the regulation of at least two developmentally important genes. An additional ttk-related cDNA clone was isolated which gives rise to an 88 kDa protein with an alternative set of zinc fingers having a DNA binding specificity distinct from that of the 69 kDa protein. Both proteins were shown to be encoded by the ttk gene through alternative splicing, providing the first example of the use of this mechanism to generate related proteins with distinct DNA binding specificities. Whole mount in situ hybridization analysis revealed different patterns of embryonic expression of the two ttk mRNA isoforms.
果蝇胚胎核提取物中的一种蛋白质能与配对规则基因even-skipped（eve）启动子和遗传学定义的自动调节元件中的多个位点结合。我们在此报告了编码这种结合活性的cDNA的分离，其序列将其鉴定为69 kDa锌指tramtrack（ttk）蛋白。由于ttk先前被认为参与控制另一个配对规则基因fushi tarazu（ftz）的表达，我们的发现表明ttk在调控至少两个对发育重要的基因中发挥作用。另外分离出一个与ttk相关的cDNA克隆，它产生一种88 kDa的蛋白质，该蛋白质具有一组不同的锌指，其DNA结合特异性与69 kDa蛋白质不同。两种蛋白质均通过可变剪接由ttk基因编码，这是利用该机制产生具有不同DNA结合特异性的相关蛋白质的首个例子。全胚胎原位杂交分析揭示了两种ttk mRNA异构体不同的胚胎表达模式。
