Massonneau Agnès, Condamine Pascal, Wisniewski Jean-Pierre, Zivy Michel, Rogowsky Peter M
RDP, UMR 5667 CNRS-INRA-ENSL-UCBL, IFR128 BioSciences Lyon-Gerland, ENS-Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France.
Biochim Biophys Acta. 2005 Jul 10;1729(3):186-99. doi: 10.1016/j.bbaexp.2005.05.004.
Comprehensive searches of maize EST data allowed us to identify 8 novel Corn Cystatin (CC) genes in addition to the previously known genes CCI and CCII. The deduced amino acid sequences of all 10 genes contain the typical cystatin family signature. In addition, they show an extended overall similarity with cystatins from other species that belong to several different phyto-cystatin subfamilies. To gain further insight into their respective roles in the maize plant, gene-specific expression profiles were established by semi-quantitative RT-PCR. While 7 CC genes were expressed in two or more tissues varying from gene to gene, CCI was preferentially expressed in immature tassels and CC8 and CC10 in developing kernels. As shown by in situ hybridisation of maize kernels, CC8 was specifically expressed in the basal region of the endosperm and CC10 both in the starchy endosperm and the scutellum of the embryo. The remaining, not kernel-specific genes, all had distinct expression kinetics during kernel development, generally with peaks during the early stages. In addition to developmental regulation, the effect of cold stress and water starvation were tested on cystatin expression. Two genes (CC8 and CC9) were induced by cold stress and 5 genes (CCII, CC3, CC4, CC5 and CC9) were down-regulated in response to water starvation. Taken together our data suggest distinct functions for CC genes in the maize plant.
对玉米EST数据进行全面检索后，我们除了先前已知的CCI和CCII基因外，还鉴定出8个新的玉米半胱氨酸蛋白酶抑制剂（CC）基因。所有10个基因推导的氨基酸序列都含有典型的半胱氨酸蛋白酶抑制剂家族特征。此外，它们与属于几个不同植物半胱氨酸蛋白酶抑制剂亚家族的其他物种的半胱氨酸蛋白酶抑制剂显示出广泛的整体相似性。为了进一步了解它们在玉米植株中的各自作用，通过半定量RT-PCR建立了基因特异性表达谱。虽然7个CC基因在不同组织中表达，且基因间表达情况不同，但CCI优先在未成熟雄穗中表达，CC8和CC10在发育中的籽粒中表达。如玉米籽粒原位杂交所示，CC8在胚乳基部区域特异性表达，CC10在胚乳淀粉质和胚盾片中均有表达。其余非籽粒特异性基因在籽粒发育过程中均有不同的表达动力学，通常在早期阶段达到峰值。除了发育调控外，还测试了冷胁迫和水分饥饿对半胱氨酸蛋白酶抑制剂表达的影响。两个基因（CC8和CC9）受冷胁迫诱导，5个基因（CCII、CC3、CC4、CC5和CC9）在水分饥饿时表达下调。综合我们的数据表明，CC基因在玉米植株中具有不同的功能。
