title: Characterization of plant eukaryotic translation initiation factor 6 (eIF6) genes: The essential role in embryogenesis and their differential expression in Arabidopsis and rice.
abstract: Eukaryotic translation initiation factor 6 (eIF6) is an essential component of ribosome biogenesis. In our present study, we characterize plant eIF6 genes for the first time. Although a single gene encodes eIF6 in yeast and animals, two genes were found to encode proteins homologous to animal and yeast eIF6 in Arabidopsis and rice, denoted At-eIF6;1 and At-eIF6;2, and Os-eIF6;1 and Os-eIF6;2, respectively. Analysis of the yeast eif6 (tif6) mutant suggested that plant eIF6, at least in the case of At-eIF6;1, can complement the essential function of eIF6 in yeast. Evidence for the essential role of eIF6 in plants was also provided by the embryonic-lethal phenotype of the at-eif6;1 mutant. In contrast, At-eIF6;2 appears not to be essential due to its very low expression level and the normal growth phenotype of the eif6;2 mutants. Consistent with the putative role of plant eIF6 in ribosome biogenesis, At-eIF6;1 is predominately expressed in tissues where cell division actively proceeds under the control of intronic cis-regulatory elements. On the other hand, both Os-eIF6;1 and Os-eIF6;2 are probably active genes because they are expressed at significant expression levels. Interestingly, the supply of ammonium nitrate as a plant nutrient was found to induce specifically the expression of Os-eIF6;2. Our present findings indicate that the eIF6 genes have differently evolved in plant and animal kingdoms and also in distinct plant species.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kato
authors.forename: Mineko
authors.initials: M
authors.lastname: Konishi
authors.forename: Mikao
authors.initials: M
authors.lastname: Shigyo
authors.forename: Tadakatsu
authors.initials: T
authors.lastname: Yoneyama
authors.forename: Shuichi
authors.initials: S
authors.lastname: Yanagisawa
mesh_terms: D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics; D039642:Eukaryotic Initiation Factors / Q000235:genetics / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000502:physiology*; D007438:Introns / Q000235:genetics; D012275:Oryza / Q000196:embryology* / Q000235:genetics
chemical_list: D039642:Eukaryotic Initiation Factors