Complete genomic structure of the bloom-forming toxic cyanobacterium Microcystis aeruginosa NIES-843.
The nucleotide sequence of the complete genome of a cyanobacterium, Microcystis aeruginosa NIES-843, was determined. The genome of M. aeruginosa is a single, circular chromosome of 5,842,795 base pairs (bp) in length, with an average GC content of 42.3%. The chromosome comprises 6312 putative protein-encoding genes, two sets of rRNA genes, 42 tRNA genes representing 41 tRNA species, and genes for tmRNA, the B subunit of RNase P, SRP RNA, and 6Sa RNA. Forty-five percent of the putative protein-encoding sequences showed sequence similarity to genes of known function, 32% were similar to hypothetical genes, and the remaining 23% had no apparent similarity to reported genes. A total of 688 kb of the genome, equivalent to 11.8% of the entire genome, were composed of both insertion sequences and miniature inverted-repeat transposable elements. This is indicative of a plasticity of the M. aeruginosa genome, through a mechanism that involves homologous recombination mediated by repetitive DNA elements. In addition to known gene clusters related to the synthesis of microcystin and cyanopeptolin, novel gene clusters that may be involved in the synthesis and modification of toxic small polypeptides were identified. Compared with other cyanobacteria, a relatively small number of genes for two component systems and a large number of genes for restriction-modification systems were notable characteristics of the M. aeruginosa genome.
Kaneko
Takakazu
T
Kazusa DNA Research Institute, 2-6-7 Kazusa-kamatari, Kisarazu, Chiba 292-0818, Japan. kaneko@kazusa.or.jp
Nakajima
Nobuyoshi
N
Okamoto
Shinobu
S
Suzuki
Iwane
I
Tanabe
Yuuhiko
Y
Tamaoki
Masanori
M
Nakamura
Yasukazu
Y
Kasai
Fumie
F
Watanabe
Akiko
A
Kawashima
Kumiko
K
Kishida
Yoshie
Y
Ono
Akiko
A
Shimizu
Yoshimi
Y
Takahashi
Chika
C
Minami
Chiharu
C
Fujishiro
Tsunakazu
T
Kohara
Mitsuyo
M
Katoh
Midori
M
Nakazaki
Naomi
N
Nakayama
Shinobu
S
Yamada
Manabu
M
Tabata
Satoshi
S
Watanabe
Makoto M
MM
D001426:Bacterial Proteins / Q000235:genetics*; D001482:Base Composition; D001483:Base Sequence; D016680:Genome, Bacterial / Q000235:genetics*; D046931:Microcystis / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins