Dwyer K G, Kandasamy M K, Mahosky D I, Acciai J, Kudish B I, Miller J E, Nasrallah M E, Nasrallah J B
Biology Department, University of Scranton, Pennsylvania 18510.
Plant Cell. 1994 Dec;6(12):1829-43. doi: 10.1105/tpc.6.12.1829.
Six sequences that are closely related to the S gene family of the largely self-incompatible Brassica species have been identified in self-fertilizing Arabidopsis. The sequences define four genomic regions that map to chromosomes 1 and 3. Of the four functional genes identified, only the previously reported Arabidopsis AtS1 gene was expressed specifically in papillar cells and may function in pollination. The remaining three genes, including two novel genes designated ARK2 and ARK3, encode putative receptor-like serine/threonine protein kinases that are expressed predominantly in vegetative tissues. ARK2 promoter activity was detected exclusively in above-ground tissues, specifically in cotyledons, leaves, and sepals, in correlation with the maturation of these structures. ARK3 promoter activity was detected in roots as well as above-ground tissues but was limited to small groups of cells in the root-hypocotyl transition zone and at the base of lateral roots, axillary buds, and pedicels. The nonoverlapping patterns of expression of the ARK genes and the divergence of their sequences, particularly in their predicted extracellular domains, suggest that these genes perform nonredundant functions in specific aspects of development or growth of the plant body.
在自花授粉的拟南芥中已鉴定出六个与主要自交不亲和的芸苔属物种的S基因家族密切相关的序列。这些序列定义了四个基因组区域，定位于第1和第3号染色体上。在鉴定出的四个功能基因中，只有先前报道的拟南芥AtS1基因在乳头细胞中特异性表达，可能在授粉过程中发挥作用。其余三个基因，包括两个新命名的ARK2和ARK3基因，编码推定的受体样丝氨酸/苏氨酸蛋白激酶，主要在营养组织中表达。ARK2启动子活性仅在地上组织中检测到，特别是在子叶、叶片和萼片中，与这些结构的成熟相关。ARK3启动子活性在根以及地上组织中均有检测到，但仅限于根-下胚轴过渡区以及侧根、腋芽和花梗基部的小细胞群。ARK基因的非重叠表达模式及其序列的差异，特别是在其预测的细胞外结构域中的差异，表明这些基因在植物身体发育或生长的特定方面发挥非冗余功能。
