THE EXPRESSION OF SERINE CARBOXYPEPTIDASES DURING MATURATION AND GERMINATION OF THE BARLEY-GRAIN
THE EXPRESSION OF SERINE CARBOXYPEPTIDASES DURING MATURATION AND GERMINATION OF THE BARLEY-GRAIN
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DOI：
10.1073/pnas.91.17.8209
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发表时间：
1994-08-16
影响因子：
11.1
通讯作者：
VON WETTSTEIN, D
中科院分区：
文献类型：
--
作者：
DALDEGAN, F;ROCHER, A;VON WETTSTEIN, D
从赤霉酸诱导的大麦糊粉cDNA文库中分离出编码另外三种丝氨酸羧肽酶（Ser-CPs）的cDNA克隆。这三个推导的Ser-CP属于Ser-CP的双链亚家族;它们作为前体合成，在A和B链之间具有推定的信号肽、前肽和接头肽。它们的鉴定为谷物中存在三种以上的Ser-CP提供了证据，并且基于它们的序列，它们可能表现出新的底物特异性。通过北方和西方分析以及RNA PCR研究了这些和先前从大麦谷粒中分离的三种Ser-CP（CP-MI、CP-MII和CP-MIII）的表达。CP-MII是在发育中的谷粒中表达和积累的唯一Ser-CP，并以其活性形式储存在成熟谷粒中。所有六种Ser-CP在萌发的谷粒中、在盾片中和/或在糊粉层中从头表达。此外，至少CP-MI、CP-MIII和CP-MIII被分泌到胚乳中。此外，所有Ser-CP（除了CP-MI）也在生长的幼苗的根和芽中表达。因此，这个酶家族似乎是无处不在的大麦植物，这表明Ser-CP发挥额外的作用，除了他们参与动员的存储蛋白。
cDNA clones encoding three additional serine carboxypeptidases (Ser-CPs) have been isolated from a gibberellic acid-induced barley aleurone cDNA library. The three deduced Ser-CPs belong to the two-chain subfamily of Ser-CPs; they are synthesized as precursors with a putative signal peptide, propeptide, and linker peptide between the A and B chains. Their identification provides the proof for the existence of more than three Ser-CPs in cereal grains, and, based on their sequences, they mag exhibit new substrate specificities. The expression of these and of the three previously isolated Ser-CPs from barley grains (CP-MI, CP-MII, and CP-MIII) has been investigated by Northern and Western analysis and RNA PCR. CP-MII is the only Ser-CP to be expressed and accumulate in the developing grain and is stored in its active form in the mature grain. All six Ser-CPs are expressed de novo in the germinating grain, in the scutellum, and/or in the aleurone. Furthermore, at least CP-MI, CP-MIII, and CP-MIII are secreted into the endosperm. In addition, all Ser-CPs (except CP-MI) are also expressed in the roots and shoots of the growing seedling. This enzyme family thus appears to be ubiquitous in the barley plant, which suggests that Ser-CPs play additional roles besides their participation in the mobilization of storage proteins.