CAJ | 학술논문

裂原激活蛋白激酶(MAPK)级联系统负责把接受自胞外或胞内的信号进一步传递和放大而最终作用于特异的转录因子,从而启动或调控基因的表达.MAPK信号级联系统在细胞分裂、分化、生物胁迫和非生物胁迫等多种信号传递途径中起着十分重要的作用.该文以一个茉莉酸(JA)诱导的表达序列为基础,在水稻中分离到了一个裂原激活蛋白激酶基因OsSJMK1的全长cDNA.序列比较分析表明该基因编码498个氨基酸,蛋白质等电点为8.43,包括完整的MAPK家族的蛋白激酶结构域.OsSJMK1与所有物种的MAPK一样包括蛋白激酶的全部11个次级结构域,在Ⅶ和Ⅷ次级结构域间一个双磷酸化位点;该位点苏氨酸(T)和酪氨酸(Y)残基之间为天冬氨酸(D),而不是其他MAPK中常见的谷氨酸(E)、脯氨酸(P)或甘氨酸(G).除了典型的MAPK激酶功能域外,在羧基端还有一段长约150个氨基酸残基的可能参与蛋白互作的结构域.以上这些结构特征表明OsSJMK1属于植物中第Ⅴ类MAPK家族成员.蛋白激酶结构域序列比较表明OsSJMK1与报道的稻瘟病菌和机械伤害诱导的BWMK1的序列相似性高达81%,而且基因内含子和外显子的组成也非常相似,属于同一亚类,但在蛋白质序列的C端差异却很大.与BWMK1不同,OsSJMK1的表达不受伤害诱导,而受稻瘟病轻微诱导,但在JA和SA(水杨酸)处理早期表达量却迅速升高.在JA处理后1 h,OsSJMK1转录水平升高到最大,而12 h后回落到处理前的本底水平;在SA处理后30 min转录水平就开始上升,2 h达到最高值,而随后开始下降到处理前的本底水平.SA类似物BTH也能诱导OsSJMK1的表达.其他一些激素处理(如ABA)和非生物胁迫(如干旱、盐胁迫)都不对基因的表达产生任何影响,而且在植物大部分组织中的表达量都非常低.这些结果说明OsSJMK1可能特异性的参与JA和SA介导的防卫反应.
렬원격활단백격매(MAPK)급련계통부책파접수자포외혹포내적신호진일보전체화방대이최종작용우특이적전록인자,종이계동혹조공기인적표체.MAPK신호급련계통재세포분렬、분화、생물협박화비생물협박등다충신호전체도경중기착십분중요적작용.해문이일개말리산(JA)유도적표체서렬위기출,재수도중분리도료일개렬원격활단백격매기인OsSJMK1적전장cDNA.서렬비교분석표명해기인편마498개안기산,단백질등전점위8.43,포괄완정적MAPK가족적단백격매결구역.OsSJMK1여소유물충적MAPK일양포괄단백격매적전부11개차급결구역,재Ⅶ화Ⅷ차급결구역간일개쌍린산화위점;해위점소안산(T)화락안산(Y)잔기지간위천동안산(D),이불시기타MAPK중상견적곡안산(E)、포안산(P)혹감안산(G).제료전형적MAPK격매공능역외,재최기단환유일단장약150개안기산잔기적가능삼여단백호작적결구역.이상저사결구특정표명OsSJMK1속우식물중제Ⅴ류MAPK가족성원.단백격매결구역서렬비교표명OsSJMK1여보도적도온병균화궤계상해유도적BWMK1적서렬상사성고체81%,이차기인내함자화외현자적조성야비상상사,속우동일아류,단재단백질서렬적C단차이각흔대.여BWMK1불동,OsSJMK1적표체불수상해유도,이수도온병경미유도,단재JA화SA(수양산)처리조기표체량각신속승고.재JA처리후1 h,OsSJMK1전록수평승고도최대,이12 h후회락도처리전적본저수평;재SA처리후30 min전록수평취개시상승,2 h체도최고치,이수후개시하강도처리전적본저수평.SA유사물BTH야능유도OsSJMK1적표체.기타일사격소처리(여ABA)화비생물협박(여간한、염협박)도불대기인적표체산생임하영향,이차재식물대부분조직중적표체량도비상저.저사결과설명OsSJMK1가능특이성적삼여JA화SA개도적방위반응.
On the basis of a JA-inducible EST, the full length cDNA of a putative protein kinase gene, OsSJMK1, was isolated from rice (Oryza sativa L.). The predicted protein of this gene, consisting of 498 amino acids with a predicted PI value of 8.43, contains a mitogen-activated protein kinase (MAPK) domain with a dual-phosphorylation activation motif TDY (Thr-Asp-Tyr) and a C-terminus domain that feature a typical MAPK belonging to subgroup V. OsSJMK1 showed 81% sequence identity to the reported BWMK1, a blast fungus and wounding inducible protein, in the N-terminus kinase domain but had low sequence identity in the C-terminus domain. Despite the high similarity of gene structure between OsSJMK1 and BWMK1, the expression of OsSJMK1 was weakly induced by blast fungus but not wounding, rather it was transiently induced by jasmonic acid (JA) and salicylic acid (SA) at early stages of treatment. This gene was not induced by other hormones (such as ABA) or abiotic stresses, such as drought and salinity. The low level of transcript of this gene was detected in the various tissues of rice. The results suggest that OsSJMK1 might be activated specifically by JA and SA and involved in defense signaling pathways.