MULTIALLELIC RECOGNITION - NONSELF-DEPENDENT DIMERIZATION OF THE BE AND BW HOMEODOMAIN PROTEINS IN USTILAGO-MAYDIS
MULTIALLELIC RECOGNITION - NONSELF-DEPENDENT DIMERIZATION OF THE BE AND BW HOMEODOMAIN PROTEINS IN USTILAGO-MAYDIS
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DOI：
10.1016/0092-8674(95)90372-0
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发表时间：
1995-04-07
期刊：
影响因子：
64.5
通讯作者：
KAHMANN, R
中科院分区：
文献类型：
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作者：
KAMPER, J;REICHMANN, M;KAHMANN, R
玉米黑粉菌（Ustilago maydis）的有性和致病性发育受多等位基因B交配型基因座控制。B基因座编码一对不相关的同源结构域蛋白，称为bE和bW，在两种多肽的N-末端结构域中具有等位基因差异聚类。只有不同等位基因来源的bE和bW的组合才有活性。我们已经研究了这种细胞内自我/非自我识别现象的潜在分子机制。通过使用双杂交系统，我们能够表明，bE和bW二聚体，只有当它们来自不同的等位基因。二聚化涉及N-末端可变结构域。分离出与bW 2组合起作用的bE 2的不同点突变体。大多数这样的bE 2突变多肽也能够在双杂交系统中与bW 2形成异二聚体。非自我依赖的二聚体的bE和bW的支持与固定化蛋白质的生化相互作用测定。我们的研究结果提出了一个模型，自我/nonself识别中，可变的凝聚力接触直接二聚化。
In the plant pathogenic fungus Ustilago maydis, sexual and pathogenic development are controlled by the multiallelic b mating-type locus. The b locus encodes a pair of unrelated homeodomain proteins termed bE and bW, with allelic differences clustering in the N-terminal domains of both polypeptides. Only combinations of bE and bW of different allelic origin are active. We have investigated the underlying molecular mechanism for this intracellular self/nonself recognition phenomenon. By using the two-hybrid system, we were able to show that bE and bW dimerize only if they are derived from different alleles. Dimerization involves the N-terminal variable domains. Different point mutants of bE2 were isolated that function in combination with bW2. The majority of such bE2 mutant polypeptides were also able to form heterodimers with bW2 in the two-hybrid system. Nonself-dependent dimerization of bE and bW was supported with a biochemical interaction assay with immobilized proteins. Our results suggest a model for self/nonself recognition in which variable cohesive contacts direct dimerization.