A novel type of DNA curvature present in a Clostridium perfringens ferredoxin gene: characterization and role in gene expression.
This study has revealed that a Clostridium perfringens ferredoxin gene (per-fdx) possesses a novel type of DNA curvature, which is formed by five phased A-tracts extending from upstream to downstream of the -35 region. The three A-tracts upstream of the promoter and the two within the promoter are located at the positions corresponding to A-tracts present in a C. perfringens phospholipase C gene (plc) and a Clostridium pasteurianum ferredoxin gene (pas-fdx), respectively. DNA fragments of the per-fdx, pas-fdx and plc genes (nucleotide positions -69 to +1 relative to the transcription initiation site) were fused to a chloramphenicol acetyltransferase reporter gene on a plasmid, pPSV, and their in vivo promoter activities were examined by assaying the chloramphenicol acetyltransferase activity of each C. perfringens transformant. Comparison of the three constructs showed that the order of promoter activity is, in descending order, per-fdx, pas-fdx and plc. Deletion of the three upstream A-tracts of the per-fdx gene drastically decreased the promoter activity, as demonstrated previously for the plc promoter. Substitution of the most downstream A-tract decreased the promoter activities of the per-fdx and pas-fdx genes. These results indicate that not only the phased A-tracts upstream of the promoter but also those within the promoter stimulate the promoter activity, and suggest that the high activity of the per-fdx promoter is due to the combined effects of these two types of A-tracts.
Kaji
Masato
M
Department of Hospital Pharmacy, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Matsushita
Osamu
O
Department of Microbiology, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Tamai
Eiji
E
Department of Microbiology, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Miyata
Shigeru
S
Department of Microbiology, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Taniguchi
Yuki
Y
Department of Microbiology, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Shimamoto
Seiko
S
Department of Microbiology, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Katayama
Seiichi
S
Department of Biochemistry, Faculty of Science, Okayama University of Science, 1-1, Ridai-cho, Okayama 700-0005, Japan.
Morita
Shushi
S
Department of Hospital Pharmacy, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Okabe
Akinobu
A
Department of Microbiology, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
D000595:Amino Acid Sequence; D001483:Base Sequence; D003016:Clostridium perfringens / Q000235:genetics*; D017931:DNA Primers; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics*; D005288:Ferredoxins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic / Q000235:genetics
D017931:DNA Primers; D004269:DNA, Bacterial; D005288:Ferredoxins