Kanegae Hiromi, Miyoshi Kazumaru, Hirose Tatsuro, Tsuchimoto Suguru, Mori Masaki, Nagato Yasuo, Takano Makoto
Molecular Genetics Department, National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan.
Plant Physiol Biochem. 2005 Jul;43(7):669-79. doi: 10.1016/j.plaphy.2005.06.004.
The rice sucrose non-fermenting-1 related protein kinase 1 (SnRK1) family consists of three genes, which were named OSK1, OSK24 and OSK35. In order to elucidate the distinct functions of OSK genes, we identified precise regions for their expression by the promoter: GUS expression analyses as well as in situ mRNA localization experiments. At first, we isolated genomic clones corresponding to each member of OSKs in order to obtain the promoter sequences. All OSK genes house 11 exons and 10 introns and the positions of introns within the coding regions are fully conserved in all these genes. Histochemical analyses using OSK promoter: beta-glucronidase (OSKP:GUS) reporter genes showed that expression patterns of OSK1P:GUS and OSK24P:GUS were quite different in the developing caryopsis. The expression of OSK1P:GUS was nearly restricted in the vascular tissues during the caryopsis development. In contrast, the OSK24P:GUS expression was detected in the pericarp at the early stage with a shift to the endosperm as the endosperm cells were formed, and GUS staining was confined to both aleurone layer and endosperm cells around 15 days after flowering, when cell division of cellular endosperm were almost finished. The shifting pattern of the OSK24 expression was correlated with the appearance of starch granules in each tissue. Similar correlation between OSK24 expression and emergence of starch granules was also observed at another temporal sink organ, the basal part of leaf sheath. These results suggest that OSK24 (rice SnRK1b) most probably have a special role in carbohydrate metabolism of the sink organs.
水稻蔗糖非发酵-1相关蛋白激酶1（SnRK1）家族由三个基因组成，分别命名为OSK1、OSK24和OSK35。为了阐明OSK基因的不同功能，我们通过启动子：GUS表达分析以及原位mRNA定位实验确定了它们表达的精确区域。首先，我们分离了与每个OSK成员相对应的基因组克隆，以获得启动子序列。所有OSK基因都有11个外显子和10个内含子，并且编码区域内内含子的位置在所有这些基因中完全保守。使用OSK启动子：β-葡萄糖醛酸酶（OSKP:GUS）报告基因的组织化学分析表明，OSK1P:GUS和OSK24P:GUS在发育中的颖果中的表达模式有很大不同。在颖果发育过程中，OSK1P:GUS的表达几乎局限于维管组织。相反，在早期阶段，OSK24P:GUS在果皮中被检测到，随着胚乳细胞的形成，表达转移到胚乳，并且在开花后约15天，GUS染色局限于糊粉层和胚乳细胞，此时细胞型胚乳的细胞分裂几乎完成。OSK24表达的转移模式与每个组织中淀粉颗粒的出现相关。在另一个临时库器官——叶鞘基部，也观察到了OSK24表达与淀粉颗粒出现之间的类似相关性。这些结果表明，OSK24（水稻SnRK1b）很可能在库器官的碳水化合物代谢中具有特殊作用。
