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Recognition sites of bovine mitochondrial serine tRNA specific for condons AGY [tRNA(Ser) (AGY)] by the cognate mitochondrial seryl-tRNA synthetase were studied using a range of tRNA(Ser)(AGY) variants which were obtained by the in vitro transcription of synthetic tRNA genes with T7 RNA polymerase. Base replacements in the anticodon and discriminator sites did not affect serine acceptance. However, deletion and/or replacement in the T-loop region completely deprived the variants of their charging activities. Point mutation experiments in this region also showed that the adenosine residue in the middle of the T-loop (position 58), which is involved in tertiary interaction between the T-loop and the truncated D-arm [de Bruijn and Klug, 1983] played a significant role in the recognition process by the synthetase.

To analyze the genes related to the pathophysiology of sporadic amyotrophic lateral sclerosis (SALS) we performed gene pro¢ling of SALS spinal cords using molecular indexing combined with cDNA microarray. Eighty-four fragments were cloned in the ¢rst screening procedure with molecular indexing. Subsequent quantitative microarray screening revealed 11 genes which were di¡erentially expressed in SALS. Real-time RT-PCR veri¢ed that the expression level of the following six genes was altered in SALS: dor¢n, metallothionein-3, 30 kDa TATAbinding protein-associated factor, neugrin, ubiquitin-like protein 5 and macrophage-inhibiting factor-related protein-8. These results indicated that genes associated with the ubiquitin^protea-some system, oxidative toxicity, transcription, neuronal di¡er-entiation and in£ammation might be involved in the pathogenesis of SALS.

The upstream region of the isocitrate lyase gene (UPR-ICL, 1530bp) of an n-alkane-utilizable yeast, Candida tropicalis, induced gene expression in another yeast, Saccharomyces cerevisiae, when the yeasts were grown on acetate. Surprisingly, UPR-ICL displayed the same regulatory function in the bacterium Escherichia coli when grown on acetate. We determined the interesting nucleotide sequence of UPR-ICL. The deletion analysis of UPR-ICL in both cells revealed the presence of two distinct promoters: one was localized at -394 to -379 and regulated gene expression in S. cerevisiae; the other was located near the initiation codon and regulated gene expression in E. coli. The two promoter sequences were similar, but not identical to regulatory elements that have been previously reported in S. cerevisiae and E. coli, respectively. Accordingly, the possibility of novel regulatory mechanisms could not be excluded. This is an interesting example of the presence of distinct cis-acting regulatory elements responsible for the induction of gene expression in one gene by acetate in both S. cerevisiae and E. coli. Preservation of such promoters through evolution is also discussed.

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