Xu P, Narasimhan M L, Samson T, Coca M A, Huh G H, Zhou J, Martin G B, Hasegawa P M, Bressan R A
Center for Plant Environmental Stress Physiology, 1165 Horticulture Building, Purdue University, West Lafayette, Indiana 47907-1165, USA.
Plant Physiol. 1998 Nov;118(3):867-74. doi: 10.1104/pp.118.3.867.
Ethylene-responsive element-binding proteins (EREBPs) of tobacco (Nicotiana tabacum L.) bind to the GCC box of many pathogenesis-related (PR) gene promoters, including osmotin (PR-5). The two GCC boxes on the osmotin promoter are known to be required, but not sufficient, for maximal ethylene responsiveness. EREBPs participate in the signal transduction pathway leading from exogenous ethylene application and pathogen infection to PR gene induction. In this study EREBP3 was used as bait in a yeast two-hybrid interaction trap with a tobacco cDNA library as prey to isolate signal transduction pathway intermediates that interact with EREBPs. One of the strongest interactors was found to encode a nitrilase-like protein (NLP). Nitrilase is an enzyme involved in auxin biosynthesis. NLP interacted with other EREBP family members, namely tobacco EREBP2 and tomato (Lycopersicon esculentum L.) Pti4/5/6. The EREBP2-EREBP3 interaction with NLP required part of the DNA-binding domain. The specificity of interaction was further confirmed by protein-binding studies in solution. We propose that the EREBP-NLP interaction serves to regulate PR gene expression by sequestration of EREBPs in the cytoplasm.
烟草（Nicotiana tabacum L.）的乙烯应答元件结合蛋白（EREBPs）可与许多病程相关（PR）基因启动子的GCC盒结合，包括渗透素（PR - 5）。已知渗透素启动子上的两个GCC盒对于最大程度的乙烯应答是必需的，但并不充分。EREBPs参与从外源乙烯处理和病原体感染到PR基因诱导的信号转导途径。在本研究中，EREB3被用作酵母双杂交相互作用陷阱中的诱饵，以烟草cDNA文库作为猎物，来分离与EREBPs相互作用的信号转导途径中间体。发现其中一个最强的相互作用蛋白编码一种腈水解酶样蛋白（NLP）。腈水解酶是一种参与生长素生物合成的酶。NLP与其他EREBPs家族成员相互作用，即烟草EREB2和番茄（Lycopersicon esculentum L.）Pti4/5/6。EREB2与EREB3和NLP的相互作用需要部分DNA结合结构域。通过溶液中的蛋白质结合研究进一步证实了相互作用的特异性。我们提出，EREBPs与NLP的相互作用通过将EREBPs隔离在细胞质中来调节PR基因的表达。
