水稻 ADP-葡萄糖焦磷酸化酶小亚基 I 基因的启动子分析

Promoter Analysis of the Gene Encoding ADP-Glucose Pyrophosphorylase Small Subunit I in Rice

摘要:

水稻(Oryaz sativa L.)基因组中的ADP-葡萄糖焦磷酸化酶小亚基(ADP-Glucose pyrophosphorylase small subunit, OsAgpS)由两个基因编码，即OsAgpS1和OsAgpS2。其中OsAgpS1基因产生两个转录本OsAgpS1a和OsAgpS1b，区别在第一个外显子的位置不同。通过RT-PCR方法分析了两个转录本在水稻组织和胚乳不同发育时期的表达特性；同时通过报告基因GUS检测了两个转录本上游转录调节区DNA片段的转录启动特性。结果表明，两个启动子与其下游转录本的表达模式完全一致，即OsAgpS1a转录本和OsAgpS1a上游启动子控制的GUS基因主要在胚乳中高水平表达，在叶片中有很低水平的表达；而OsAgpS1b转录本和OsAgpS1b上游启动子控制的GUS基因主要在叶片和胚乳发育早期低水平表达。这说明OsAgpS1基因产生的两个转录本是由不同的启动子控制转录的，OsAgpS1a上游启动子可以作为胚乳表达用启动子。

Abstract:

Two distinct genes, OsAgpS1 and OsAgpS2, were found to encode ADP-Glucose pyrophosphorylase small subunit in rice (Oryaz sativa L.) genome. While OsAgpS1 gives rise to two different transcripts, OsAgpS1a and OsAgpS1b, through alternative splicing at the first exon. The expression patterns of the two transcripts in different tissues and developing endosperms in rice were analyzed by RT-PCR. On the other hand, the spatial regulation of OsAgpS1gene expression by using a reporter gene GUS driven by two different promoters upstream the two transcripts, respectively, were analyzed. The results showed that OsAgpS1a transcripts and the reporter gene GUS driven by the OsAgpS1a promoter had a similar expression pattern that abundantly expressed in endosperms but very low in leaves, whereas OsAgpS1b transcripts and the reporter gene GUS driven by the OsAgpS1b promoter own other similar expression pattern that expressed at a low level in leaves, roots and early development endosperms of rice. These results suggested that these two different transcripts of OsAgpS1 gene were driven by different promoters, and the promoter upstream OsAgpS1a could be used as an endosperm specific expression promoter in rice.