Rogers H J, Bate N, Combe J, Sullivan J, Sweetman J, Swan C, Lonsdale D M, Twell D
Cardiff School of Biosciences, Cardiff University, UK.
Plant Mol Biol. 2001 Mar;45(5):577-85. doi: 10.1023/a:1010695226241.
The tobacco gene g10 is preferentially and maximally expressed in mature pollen, shows homology to pectate lyases, and is the putative homologue of the tomato gene lat56. Analysis of regulatory elements within the g10 promoter was carried out to verify the importance of putative regulatory sequence motifs. Analysis of transgenic plants showed that 1190 bp of g10 5' sequence directed preferential expression of GUS in pollen, with bimodal peaks of expression just before and during pollen mitosis I, and in mature anthers. This was confirmed by northern analysis of native g10 transcripts in isolated spores. Transient expression analysis defined the minimal g10 promoter region capable of directing expression in pollen as -86 to +217. Three upstream regions within -427 bp modulate the expression from g10. Gain-of-function analyses showed that the region from -106 to -53 could enhance pollen-specific expression of a minimal CaMV 35S promoter. These analyses further showed that sequences upstream of -86 modulate expression in pollen, but are not essential for preferential pollen expression. The function of a conserved GTGA motif shared between the tobacco g10 and tomato lat56 promoters was demonstrated in g10. Thus, further functional evidence is provided for the conservation of mechanisms for the regulation of late pollen genes across species.
烟草基因g10在成熟花粉中优先且最大程度地表达，与果胶酸裂解酶具有同源性，并且是番茄基因lat56的推定同源物。对g10启动子内的调控元件进行分析以验证推定调控序列基序的重要性。对转基因植物的分析表明，g10 5'序列的1190 bp指导GUS在花粉中的优先表达，在花粉有丝分裂I之前和期间以及在成熟花药中具有双峰表达峰值。这通过对分离孢子中天然g10转录本的Northern分析得到证实。瞬时表达分析确定了能够指导花粉中表达的最小g10启动子区域为-86至+217。-427 bp内的三个上游区域调节g10的表达。功能获得分析表明，-106至-53区域可以增强最小CaMV 35S启动子的花粉特异性表达。这些分析进一步表明，-86上游的序列调节花粉中的表达，但对于花粉优先表达不是必需的。在g10中证明了烟草g10和番茄lat56启动子之间共享的保守GTGA基序的功能。因此，为跨物种晚期花粉基因调控机制的保守性提供了进一步的功能证据。
