Arenas-Mena C, Raynal M, Borrell A, Varoquaux F, Cutanda M C, Stacy R A, Pagès M, Delseny M, Culiáñez-Macià F A
Departament de Genètica Molecular, Centre d'Investigació i Desenvolupament, C.S.I.C., Barcelona, Spain.
Plant Mol Biol. 1999 May;40(2):355-63. doi: 10.1023/a:1006219315562.
The maize abscisic acid (ABA)-responsive gene rab28 has been shown to be ABA-inducible in embryos and vegetative tissues, expression being mostly restricted to vascular elements during late embryogenesis. In the course of an expressed sequence tags (ESTs) programme, we have isolated an Arabidopsis thaliana gene, Atrab28, encoding the orthologue of maize rab28. The Atrab28 cDNA is 1090 bp long, including a poly(A)+ stretch, and encodes a polypeptide of 262 amino acids. Atrab28 antibody against the recombinant protein recognizes a polipeptide of about 30 kDa and pI 6, in close agreement with the predicted molecular mass and pI. As for maize rab28, expression studies with Atrab28 revealed high specificity for embryo tissues, transcription being stimulated by the transcriptional activator abi3. In contrast, Atrab28 was not induced in vegetative tissues by ABA, osmotic stress or dehydration. The expression of Atrab28 mRNA and the accumulation of Atrab28 protein was largely restricted to provascular tissues of mature embryos and in the seed coat outer tegument and embryo and silique epidermis, as revealed by in situ hybridization and immunocytochemistry with anti-Atrab28 antibodies.
玉米脱落酸（ABA）响应基因rab28已被证明在胚胎和营养组织中可被ABA诱导，在胚胎发育后期其表达大多局限于维管组织。在一个表达序列标签（ESTs）项目过程中，我们分离出了拟南芥基因Atrab28，它编码玉米rab28的直系同源物。Atrab28 cDNA长1090 bp，包括一个聚腺苷酸（poly(A)+）序列，编码一个由262个氨基酸组成的多肽。针对重组蛋白的Atrab28抗体识别出一条约30 kDa且pI为6的多肽，这与预测的分子量和pI非常一致。与玉米rab28一样，对Atrab28的表达研究表明其对胚胎组织具有高度特异性，转录受转录激活因子abi3的刺激。相比之下，Atrab28在营养组织中不会被ABA、渗透胁迫或脱水诱导。原位杂交和用抗Atrab28抗体进行的免疫细胞化学显示，Atrab28 mRNA的表达和Atrab28蛋白的积累大多局限于成熟胚胎的原维管组织以及种皮外层、胚胎和角果表皮。
