HORMONAL-REGULATION, PROCESSING, AND SECRETION OF CYSTEINE PROTEINASES IN BARLEY ALEURONE LAYERS
HORMONAL-REGULATION, PROCESSING, AND SECRETION OF CYSTEINE PROTEINASES IN BARLEY ALEURONE LAYERS
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DOI：
10.1105/tpc.2.8.769
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发表时间：
1990-08-01
期刊：
影响因子：
11.6
通讯作者：
HO, THD
中科院分区：
文献类型：
--
作者：
KOEHLER, SM;HO, THD
大麦糊粉蛋白层对赤霉素（GA3）的反应合成和分泌多种蛋白酶。有两种主要的半胱氨酸蛋白酶被称为EP-A （37,000 Mr）和EP-B (30,000 Mr) [Koehler and Ho(1988)]。植物生理学报[j]。我们现在报道了EP-B的cDNA克隆，并描述了这两种半胱氨酸蛋白酶的翻译后加工和激素调节。从ga3诱导的大麦糊粉层中克隆了3个半胱氨酸蛋白酶cdna。基因组DNA凝胶印迹分析表明，这些都是一个小基因家族的成员，不超过4到5个不同的基因。其中两个克隆（pHVEP1和4）编码的蛋白质彼此相似性达98%，都是EP-B的同工酶。该蛋白含有大量的前序序列，随后是纯化EP-B的成熟N端氨基酸序列，并且对EP-B抗血清具有抗原性。脉冲追踪实验结果表明，大序列的翻译后处理以多步骤的方式进行，以产生成熟的酶。在糊粉层和周围的培养培养基中都可以观察到EP-B的加工中间体，但只有成熟的EP-A才会分泌。在蛋白和mRNA水平上比较EP-A、EP-B和其他糊粉半胱氨酸蛋白酶的合成调控。我们得出结论，大麦糊粉半胱氨酸蛋白酶在时间和激素诱导的表达方面受到差异调节。
Barley aleurone layers synthesize and secrete several proteases in response to gibberellic acid (GA3). Two major cysteine proteinases designated EP-A (37,000 Mr) and EP-B (30,000 Mr) have been described [Koehler and Ho (1988). Plant Physiol. 87, 95-103]. We now report the cDNA cloning of EP-B and describe the post-translational processing and hormonal regulation of both cysteine proteinases. Three cDNAs for cysteine proteinases were cloned from GA3-induced barley aleurone layers. Genomic DNA gel blot analysis indicated that these are members of a small gene family with no more than four to five different genes. The proteins encoded by two of these clones, pHVEP1 and 4, are 98% similar to each other and are isozymes of EP-B. The proteins contain large preprosequences followed by the amino acid sequence described as the mature N terminus of purified EP-B, and are antigenic to EP-B antiserum. The results of pulse-chase experiments indicated that the post-translational processing of large prosequences proceeds in a multistep fashion to produce the mature enzymes. Processing intermediates for EP-B are observed both in the aleurone layers and surrounding incubation medium, but only mature EP-A is secreted. The regulation of synthesis of EP-A, EP-B, and other aleurone cysteine proteinases was compared at the protein and mRNA levels. We conclude that barley aleurone cysteine proteinase are differentially regulated with respect to their temporal and hormonally induced expression.