Benassayag C, Seroude L, Boube M, Erard M, Cribbs D L
Centre de Biologie du Développement-CNRS, Toulouse, France.
Mech Dev. 1997 May;63(2):187-98. doi: 10.1016/s0925-4773(97)00040-3.
The Drosophila homeotic gene proboscipedia (pb: HoxA2/B2 homolog) is required for adult mouthparts development. Ectopic PB protein expression from a transgenic Hsp70-pb minigene (HSPB) results in transformation of adult antennae to maxillary palps. In contrast, most tissues appear refractory to PB-induced effects. To study the basis of homeotic tissue specificity we are isolating and studying mutations that modify dominant HSPB-induced phenotypes. One HSPB point mutation (Arg5 of the homeodomain to His) removes homeotic activity in the mouthparts and antennae, but provokes a dose-sensitive eye loss. We show that eye loss can be induced by PB proteins that no longer effectively bind to DNA. The dose-sensitive eye loss thus appears to be mediated by specific, context-dependent protein-protein interactions.
果蝇同源异型基因触须基因（pb：HoxA2/B2同源物）是成虫口器发育所必需的。来自转基因Hsp70-pb小基因（HSPB）的异位PB蛋白表达会导致成虫触角转变为上颌触须。相比之下，大多数组织似乎对PB诱导的效应具有抗性。为了研究同源异型组织特异性的基础，我们正在分离和研究能够改变显性HSPB诱导表型的突变。一个HSPB点突变（同源结构域的第5位精氨酸突变为组氨酸）消除了口器和触角中的同源异型活性，但会引发剂量敏感的眼睛缺失。我们表明，不再能有效结合DNA的PB蛋白可诱导眼睛缺失。因此，剂量敏感的眼睛缺失似乎是由特定的、依赖于上下文的蛋白质-蛋白质相互作用介导的。
