Wakeley P R, Rogers H J, Rozycka M, Greenland A J, Hussey P J
School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK.
Plant Mol Biol. 1998 May;37(1):187-92. doi: 10.1023/a:1005954621558.
Pectin methylesterase (PME) is responsible for the demethylation of pectin prior to pectin's degradation by the combined activities of polygalacturonase and pectate lyase. We have differentially screened a maize pollen cDNA library to detect cDNA clones whose genes are specifically expressed in pollen. One group of clones resulting from this screen showed similarity (between 18% and 41% identity) with plant and fungal PMEs. The full-length clone from this group, ZmC5, identifies a small gene family (at least 2 members) when used as a probe on genomic Southern blots. Northern analysis reveals that the ZmC5 transcript is expressed specifically in late pollen development. This tissue-specific gene expression programme is further confirmed in transgenic tobacco plants harbouring ZmC5 promoter/GUS chimeric gene constructs.
果胶甲酯酶（PME）负责在果胶被多聚半乳糖醛酸酶和果胶酸裂解酶的联合作用降解之前使其去甲基化。我们通过差异筛选玉米花粉cDNA文库来检测其基因在花粉中特异性表达的cDNA克隆。该筛选产生的一组克隆与植物和真菌的PME显示出相似性（同一性在18%至41%之间）。当将该组中的全长克隆ZmC5用作基因组Southern杂交的探针时，鉴定出一个小基因家族（至少2个成员）。Northern分析表明ZmC5转录本在花粉发育后期特异性表达。在携带ZmC5启动子/GUS嵌合基因构建体的转基因烟草植株中进一步证实了这种组织特异性基因表达模式。
