Cloning and characterization of CER2, an Arabidopsis gene that affects cuticular wax accumulation
Cloning and characterization of CER2, an Arabidopsis gene that affects cuticular wax accumulation
复制标题
DOI：
10.1105/tpc.8.8.1291
复制
发表时间：
1996-08-01
期刊：
影响因子：
11.6
通讯作者：
Schnable, PS
中科院分区：
文献类型：
--
作者：
Xia, YJ;Nicolau, BJ;Schnable, PS
表皮蜡是覆盖植物表面的非常长链脂肪酸及其衍生物的复杂混合物。拟南芥的ECERIFERUM 2（cer 2）基因的突变体调节明亮的绿色茎和长角果，这表明在野生型植物上包含蜡花的表皮蜡晶体的相对低丰度。我们通过染色体步移克隆了CER 2基因。有三条证据表明克隆的序列代表了CER 2基因：（1）该序列能够补充转基因植物中的cod突变体表型;（2）从cer 2 -2突变等位基因纯合的植物中分离的相应DNA序列含有产生提前终止密码子的序列多态性;和（3）推导的CER 2蛋白质序列显示出与玉米基因（glossy 2）的序列相似性，该玉米基因也参与表皮蜡积累。CER 2基因编码一种新的蛋白质，预测分子量为47 kD。我们研究了CER 2基因的表达模式，通过原位杂交和分析的转基因拟南芥植物携带CER 2-β-葡萄糖醛酸酶基因融合，包括1.0 kb的CER 2和0.2 kb的CER 2编码序列的上游。这些研究表明，CER 2基因是在一个器官和组织特异性的方式表达; CER 2仅在年轻的角果和茎的表皮中高水平表达。这一发现与CER 2基因突变体相关的可见表型一致。因此，用于构建CER 2-β-葡萄糖醛酸苷酶基因融合体的CER 2基因的1.2-kb片段包括CER 2 mRNA的表皮特异性积累所需的所有遗传信息。
Cuticular waxes are complex mixtures of very long chain fatty acids and their derivatives that cover plant surfaces. Mutants of the ECERIFERUM2 (cer2) gene of Arabidopsis condition bright green stems and siliques, indicative of the relatively low abundance of the cuticular wax crystals that comprise the wax bloom on wild-type plants. We cloned the CER2 gene via chromosome walking. Three lines of evidence establish that the cloned sequence represents the CER2 gene: (1) this sequence is capable of complementing the cod mutant phenotype in transgenic plants; (2) the corresponding DNA sequence isolated from plants homozygous for the cer2-2 mutant allele contains a sequence polymorphism that generates a premature stop codon; and (3) the deduced CER2 protein sequence exhibits sequence similarity to that of a maize gene (glossy2) that also is involved in cuticular wax accumulation. The CER2 gene encodes a novel protein with a predicted mass of 47 kD. We studied the expression pattern of the CER2 gene by in situ hybridization and analysis of transgenic Arabidopsis plants carrying a CER2-beta-glucuronidase gene fusion that includes 1.0 kb immediately upstream of CER2 and 0.2 kb of CER2 coding sequences. These studies demonstrate that the CER2 gene is expressed in an organ- and tissue-specific manner; CER2 is expressed at high levels only in the epidermis of young siliques and stems. This finding is consistent with the visible phenotype associated with mutants of the CER2 gene. Hence, the 1.2-kb fragment of the CER2 gene used to construct the CER2-beta-glucuronidase gene fusion includes all of the genetic information required for the epidermis-specific accumulation of CER2 mRNA.