Nagata T, Ishida S, Hasezawa S, Takahashi Y
Department of Plant Sciences, Graduate School of Science, University of Tokyo, Japan.
Int J Dev Biol. 1994 Jun;38(2):321-7.
Since the initial process of culturing tobacco mesophyll protoplasts can be considered as a model system of dedifferentiation of higher plants, the mode of expression of genes induced by auxin, a key factor in inducing dedifferentiation, has been analyzed during the regaining of meristematic activity of quiescent and differentiated tobacco mesophyll. By differential screening we have isolated three auxin-regulated genes, which we named parA, parB and parC. parA and parC, which belong to the same gene family, were supposed to play a role in transcriptional regulation upon induction by auxin, while parB encoded glutathione S-transferase. Although it was supposed that the expression of these par genes should play a pivotal role in regaining the meristematic activity of the differentiated tobacco mesophyll cells, a possibility that other less abundantly expressing genes would have been neglected in these studies has not been excluded. On the other hand, the search for genes which would be involved in maintaining cell division activity in the dedifferentiated plant cells allowed us to isolate a few genes. One of these genes, designated arcA, belonged to a beta subunit-like protein of heterotrimeric G proteins. The significance of the involvement of this gene product in maintaining the meristematic activity of plant cells cultured in vitro has been discussed.
由于烟草叶肉原生质体的初始培养过程可被视为高等植物去分化的模型系统，因此在静止和分化的烟草叶肉恢复分生组织活性的过程中，对诱导去分化的关键因素生长素所诱导基因的表达模式进行了分析。通过差异筛选，我们分离出了三个受生长素调控的基因，分别命名为parA、parB和parC。parA和parC属于同一个基因家族，推测它们在生长素诱导时参与转录调控，而parB编码谷胱甘肽S-转移酶。尽管推测这些par基因的表达在恢复分化的烟草叶肉细胞的分生组织活性中应起关键作用，但并未排除在这些研究中其他低丰度表达基因被忽视的可能性。另一方面，对参与维持去分化植物细胞分裂活性的基因的搜索使我们分离出了一些基因。其中一个基因，命名为arcA，属于异源三聚体G蛋白的β亚基样蛋白。已讨论了该基因产物参与维持体外培养植物细胞分生组织活性的意义。
