Fulton Lynette M, Cobbett Christopher S
Department of Genetics, University of Melbourne, Victoria 3010, Australia.
J Exp Bot. 2003 Nov;54(392):2467-77. doi: 10.1093/jxb/erg269. Epub 2003 Sep 25.
Glycosyl hydrolases are important mediators of plant cell wall modification during plant development. These enzymes catalyse the hydrolytic release of specific sugars, such as L-arabinose, from the polysaccharide-rich cell wall matrix. The cloning and expression analysis of two genes, AtASD1 and AtASD2, encoding putative alpha-L-arabinofuranosidases in Arabidopsis thaliana are reported here. AtASD1 and AtASD2 identities were assigned on the basis of homology to plant and microbial family 51 glycoside hydrolases. Using RT-PCR, RNA gel blot analysis and reporter gene expression analysis, AtASD1 and AtASD2 were shown to have different developmental expression profiles. High levels of AtASD1 promoter activity are present in multiple tissues during vegetative and reproductive growth. AtASD1 expression is particularly intense in zones of cell proliferation, the vascular system, developing and regressing floral tissues, and floral abscission zones. By comparison, AtASD2 expression is limited to the vasculature of older root tissue and to some floral organs and floral abscission zones.
糖基水解酶是植物发育过程中植物细胞壁修饰的重要介质。这些酶催化从富含多糖的细胞壁基质中水解释放特定的糖类，如L-阿拉伯糖。本文报道了拟南芥中两个编码假定的α-L-阿拉伯呋喃糖苷酶的基因AtASD1和AtASD2的克隆及表达分析。AtASD1和AtASD2的身份是根据与植物和微生物第51家族糖苷水解酶的同源性确定的。利用RT-PCR、RNA凝胶印迹分析和报告基因表达分析，AtASD1和AtASD2表现出不同的发育表达模式。在营养生长和生殖生长期间，多个组织中存在高水平的AtASD1启动子活性。AtASD1在细胞增殖区域、维管系统、发育中和退化的花组织以及花脱落区的表达尤为强烈。相比之下，AtASD2的表达仅限于较老根组织的维管系统以及一些花器官和花脱落区。
