寒冷バイオシステム研究センター

概要 アクセス 職員 学生 研究業績 発行物 イベント情報 担当講義科目 掲示板 サイトマップ リンク お問い合わせ

Ejiri, S. (2002)
Moonlighting functions of polypeptide elongation factor 1: From actin bundling to zinc finger protein R1-associated nuclear localization.
Biosci. Biotech. Biochem. 66: 1-21.
　Eukaryotic polypeptide elongation factor EF-1 is not only a major translational factor, but also one of the most important multifunctional (moonlighting) proteins. EF-1 consists of four different subunits collectively termed EF-1α and EF-1ββ'γ in plants and animals, respectively. EF-1α・GTP catalyzes the binding of aminoacyl-tRNA to the A-site of the ribosome. EF-ββ'γ (EF-1β and EF-β'), catalyzes GDP/GTP exchange on EF-1α・GDP to regenerate EF-1α・GTP. EF-1γ has recently been shown to have glutathione S-transferase activity. EF-2 catalyzes the translocation of peptidyl-tRNA from the A-site to the P-site on the ribosome. Recently, molecular mimicry among tRNA, elongation factors, releasing factor (RF), and ribosome recycling factor (RRF) has been demonstrated and greatly improved our understanding of the mechanism of translation.
　Moreover, eukaryotic elongation factors have been shown to be concerned or likely to be concerned in various important cellular processes or serious diseases, including translational control, signal transduction, cytoskeletal organization, apoptosis, adult atopic dermatitis, oncogenic transformation, nutrition, and nuclear processes such as RNA synthesis and mitosis.This article aims to overview the recent advances in protein biosynthesis, concentrating on the moonlighting functions of EF-1.

Kamiie, K., Nomura, Y., Kobayashi, S., Taira, H., Kobayashi, K., Matsuzawa, H., Yamashita, T., Kidou, S. and Ejiri, S. (2002)
Cloning and expression of silk gland elongation factor 1γ in Escherichia coli.
Biosci. Biotech. Biochem. 66: 558-565.
　Elongation factor 1 (EF-1) from the silk gland of Bombyx mori consists of α-, β-, β'-, and γ-subunits. EF-1α・GTP catalyzes the binding of aminoacyl- tRNA to ribosomes concomitant with the hydrolysis of GTP. EF-1ββ'γ catalyzes the exchange of EF-1α-bound GDP for exogenous GTP and stimulates the EF-1α -dependent binding of aminoacyl-tRNA to ribosomes.
　EF-1γ cDNA, which contains an open reading frame (ORF) encoding a polypeptide of 423 amino acid residues, was amplified and cloned by PCR from a silk gland cDNA library. The calculated molecular mass and predicted pI of the product were 48, 388 Da and 5.84, respectively. The silk gland EF-1γ shares 67.3％ amino acid identity with Artemia salina EF-1γ. The N-terminal domain (amino acid residues 1--211) of silk gland EF-1γ is 29.3％ identical to maize glutathione S-transferase. We demonstrated that silk gland EF-1γ bound to glutathione Sepharose, suggesting that the N-terminal domain of EF-1γ may have the capacity to bind to glutathione.

Kato, K., Kidou, S., Miura, H. and Sagawa, S. (2002)
Molecular cloning of the wheat CK2α gene and detection of its linkage with Vrn-A1 on chromosome 5A.
Theor. Appl. Genet. 104: 1071-1077.
The casein kinase CK2 is one of the major multifunctional protein kinases in cells that is expressed ubiquitously and is essential for survival. The α- subunit of CK2 is thought to be involved in light-regulated gene expression and rhythmic expression of genes by circadian rhythm in plants. The rice chromosome-3 region containing the photoperiod-response Hd6 gene, an orthologue of the CK2αgenes of Arabidopsis and maize, is in synteny with the wheat chromosome-5A Vrn-A1 region. This evidence proposes two possibilities, first the wheat Vrn-A1 is an orthologue of the rice CK2α, and second the wheat CK2αwhich has not yet been identified is located independently but tightly linked to Vrn-A1. To clarify whether the wheat CK2αgene is conserved in the Vrn-A1 region and to elucidate the above two possibilities, we attempted to isolate this gene from the wheat cDNA library and to map it on the chromosome-5A region that is syntenous to the rice Hd6 region. The isolated cDNA clone showed an extremely high homology with the Arabidopsis CK2αgene. Using this clone as a probe genomic Southern-blot analyses of the aneuploid lines available in Chinese Spring assigned the wheat homologue of CK2αto the long arm of chromosome 5A. Furthermore, a linkage analysis using an F2 population having recombination in the Vrn-A1 region revealed that the wheat CK2α, designated as tck2a, is tightly linked to Vrn-A1 by 1.1 cM