Abe K, Emori Y, Kondo H, Suzuki K, Arai S
Department of Agricultural Chemistry, University of Tokyo, Japan.
J Biol Chem. 1987 Dec 15;262(35):16793-7.
A cDNA clone for a cysteine proteinase inhibitor of rice (oryzacystatin) was isolated from a lambda gt10 cDNA library of rice immature seeds by screening with synthesized oligonucleotide probes based on partial amino acid sequences of oryzacystatin. A nearly full-length cDNA clone was obtained which encoded 102-amino acid residues. The amino acid sequence of oryzacystatin deduced from the cDNA sequence was significantly homologous to those of mammalian cystatins, especially family 2 cystatins. Oryzacystatin contained the sequence Gln-Val-Val-Ala-Gly conserved among most members of the cystatin superfamily. The gene for oryzacystatin was transcribed into a single mRNA species of about 700 nucleotides. The content of mRNA reached its highest level 2 weeks after flowering and then gradually decreased to undetectable levels at 10 weeks. This feature of transient expression is coordinate with that of glutelin (a major storage protein), although the expression of oryzacystatin precedes that of glutelin by about 1 week.
通过用基于水稻半胱氨酸蛋白酶抑制剂（水稻胱抑素）部分氨基酸序列合成的寡核苷酸探针筛选水稻未成熟种子的λgt10 cDNA文库，分离出了水稻胱抑素的cDNA克隆。获得了一个编码102个氨基酸残基的近乎全长的cDNA克隆。从cDNA序列推导的水稻胱抑素氨基酸序列与哺乳动物胱抑素，特别是第2家族胱抑素的氨基酸序列具有显著同源性。水稻胱抑素含有在胱抑素超家族大多数成员中保守的Gln-Val-Val-Ala-Gly序列。水稻胱抑素基因转录成一种约700个核苷酸的单一mRNA。mRNA含量在开花后2周达到最高水平，然后在10周时逐渐降至不可检测水平。这种瞬时表达特征与谷蛋白（一种主要的贮藏蛋白）的表达特征一致，尽管水稻胱抑素的表达比谷蛋白早约1周。
