Complete genomic structure of the bloom-forming toxic cyanobacterium Microcystis aeruginosa NIES-843.
Complete genomic structure of the bloom-forming toxic cyanobacterium Microcystis aeruginosa NIES-843.
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DOI：
10.1093/dnares/dsm026
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发表时间：
2007-12-31
期刊：
影响因子：
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通讯作者：
Watanabe MM
中科院分区：
文献类型：
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作者：
Kaneko T;Nakajima N;Okamoto S;Suzuki I;Tanabe Y;Tamaoki M;Nakamura Y;Kasai F;Watanabe A;Kawashima K;Kishida Y;Ono A;Shimizu Y;Takahashi C;Minami C;Fujishiro T;Kohara M;Katoh M;Nakazaki N;Nakayama S;Yamada M;Tabata S;Watanabe MM
测定了铜绿微囊藻NIES-843的全基因组核苷酸序列。铜绿假单胞菌基因组为单条环形染色体，全长5842795个碱基对，平均GC含量为42.3%。该染色体包括6312个编码蛋白质的基因、两组rRNA基因、代表41个tRNA物种的42个tRNA基因以及rNaseP、SRP和6Sa RNA的B亚基tmRNA基因。45%的推测蛋白质编码序列与已知功能的基因序列相似，32%与假设基因相似，其余23%与已报道的基因没有明显相似性。共688kb的基因组，相当于整个基因组的11.8%，由插入序列和微型反向重复转座元件组成。这表明铜绿假单胞菌基因组的可塑性，通过一种涉及重复DNA元件介导的同源重组的机制。除了已知的与微囊藻毒素和氰神经肽合成相关的基因簇外，还发现了可能参与有毒小肽合成和修饰的新基因簇。与其他蓝藻相比，铜绿假单胞菌基因组的显著特征是两个组分系统的基因数量相对较少，而限制修饰系统的基因数量较多。
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.