Rodriguez C M, Freire M A, Camilleri C, Robaglia C
INRA, Laboratoire de Biologie Cellulaire, Versailles, France.
Plant J. 1998 Feb;13(4):465-73. doi: 10.1046/j.1365-313x.1998.00047.x.
Two cDNAs (At.EIF4E1 and At.EIF4E2) encoding, respectively, the eukaryotic initiation factors eIF4E and eIF(iso)4E of Arabidopsis thaliana were isolated by complementation of a Saccharomyces cerevisiae conditional mutant. The deduced amino acid sequences of the proteins are homologous to those from monocotyledonous plants, yeast and mammals. The corresponding genes were identified in YAC clones mapping to chromosome IV (At.EIF4E1) and to chromosome V (At.EIF4E2). The yeast strain complemented by At.EIF4E2 grew poorly compared with an isogenic strain expressing At.EIF4E1. Northern and in situ hybridization analysis show that both Arabidopsis At.EIF4E1 and At.EIF4E2 mRNAs are differentially accumulated in plant tissues. The At.EIF4E1 mRNA is expressed in all tissues except in the cells of the specialization zone of the roots; the At.EIF4E2 mRNA is particularly abundant in floral organs and in young developing tissues. This work further demonstrates an association between a high level of EIF4E mRNAs and cell proliferation and suggests that the plant eIF4E isoforms may have distinct functions in cell development and metabolism.
通过对酿酒酵母条件突变体进行互补，分离出了分别编码拟南芥真核起始因子eIF4E和eIF(iso)4E的两个cDNA（At.EIF4E1和At.EIF4E2）。推导的蛋白质氨基酸序列与单子叶植物、酵母和哺乳动物的序列同源。在定位到第四条染色体（At.EIF4E1）和第五条染色体（At.EIF4E2）的酵母人工染色体（YAC）克隆中鉴定出了相应基因。与表达At.EIF4E1的同基因菌株相比，由At.EIF4E2互补的酵母菌株生长较差。Northern杂交和原位杂交分析表明，拟南芥At.EIF4E1和At.EIF4E2的mRNA在植物组织中的积累存在差异。At.EIF4E1的mRNA在除根特化区细胞外的所有组织中表达；At.EIF4E2的mRNA在花器官和幼嫩发育组织中特别丰富。这项工作进一步证明了高水平的EIF4E mRNA与细胞增殖之间的关联，并表明植物eIF4E同工型在细胞发育和代谢中可能具有不同的功能。
