Molecular characterization of a senescence-associated gene encoding cysteine proteinase and its gene expression during leaf senescence in sweet potato
Molecular characterization of a senescence-associated gene encoding cysteine proteinase and its gene expression during leaf senescence in sweet potato
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DOI：
10.1093/pcp/pcf125
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发表时间：
2002-09-01
影响因子：
4.9
通讯作者：
Chen, SCG
中科院分区：
文献类型：
--
作者：
Chen, GH;Huang, LT;Chen, SCG
甘薯衰老相关基因（SPG 31）编码甘薯半胱氨酸蛋白酶前体的结构和表达的特点。该基因的编码区由两个外显子组成，编码一个341个氨基酸的酶前体，具有木瓜蛋白酶保守的催化氨基酸。通过北方印迹分析检测甘薯中SPG 31基因的表达模式，揭示SPG 31的转录本在衰老叶片中特异性诱导，而在其它器官中不诱导。成熟SPG 31蛋白在衰老叶片中的差异积累通过叶片蛋白的双向电泳和N-末端测序进一步鉴定。这一结果表明，SPG 31在叶片衰老过程中的蛋白质水解和氮再动员中发挥了重要作用。此外，用乙烯处理成熟的绿色叶片3 d导致SPG 31转录物的高水平诱导。乙烯调控的SPG 31的表达与899 bp的SPG 31启动子区域中存在许多推定的乙烯响应元件是一致的。
The structure and expression of a senescence-associated gene (SPG31) encoding a cysteine proteinase precursor of sweet potato have been characterized. The coding region of the gene consists of two exons encoding an enzyme precursor of 341 amino acids with conserved catalytic amino acids of papain. Examination of the expression patterns of the SPG31 gene in sweet potato by Northern blot analyses reveals that the transcripts of SPG31 are specifically induced in the senescing leaves but not in other organs. The differential accumulation of the mature SPG31 protein in the senescing leaves was further identified by two-dimensional electrophoresis of leaf proteins and N-terminal sequencing. This result suggests the important role played by SPG31 in proteolysis and nitrogen remobilization during the leaf senescence process. Furthermore, treatment of mature green leaves with ethylene for 3 d resulted in a high-level induction of SPG31 transcripts. Ethylene-regulated expression of SPG31 is consistent with the presence of a number of putative ethylene-responsive elements in the 899-bp SPG31 promoter region.