Chambaud I, Heilig R, Ferris S, Barbe V, Samson D, Galisson F, Moszer I, Dybvig K, Wróblewski H, Viari A, Rocha E P, Blanchard A
INRA-Université de Bordeaux 2, Institut de Biologie Végétale Moléculaire, 71 avenue Edouard Bourleaux, BP 81, 33883 Villenave D'Ornon Cedex, France.
Nucleic Acids Res. 2001 May 15;29(10):2145-53. doi: 10.1093/nar/29.10.2145.
Mycoplasma pulmonis is a wall-less eubacterium belonging to the Mollicutes (trivial name, mycoplasmas) and responsible for murine respiratory diseases. The genome of strain UAB CTIP is composed of a single circular 963 879 bp chromosome with a G + C content of 26.6 mol%, i.e. the lowest reported among bacteria, Ureaplasma urealyticum apart. This genome contains 782 putative coding sequences (CDSs) covering 91.4% of its length and a function could be assigned to 486 CDSs whilst 92 matched the gene sequences of hypothetical proteins, leaving 204 CDSs without significant database match. The genome contains a single set of rRNA genes and only 29 tRNAs genes. The replication origin oriC was localized by sequence analysis and by using the G + C skew method. Sequence polymorphisms within stretches of repeated nucleotides generate phase-variable protein antigens whilst a recombinase gene is likely to catalyse the site-specific DNA inversions in major M.pulmonis surface antigens. Furthermore, a hemolysin, secreted nucleases and a glyco-protease are predicted virulence factors. Surprisingly, several of the genes previously reported to be essential for a self-replicating minimal cell are missing in the M.pulmonis genome although this one is larger than the other mycoplasma genomes fully sequenced until now.
肺支原体是一种无细胞壁的真细菌，属于柔膜菌纲（俗名：支原体），可引发鼠类呼吸道疾病。UAB CTIP菌株的基因组由一条单一的环状963879 bp染色体组成，G + C含量为26.6 mol%，即除解脲脲原体之外，在细菌中报道的最低值。该基因组包含782个推定的编码序列（CDS），覆盖其长度的91.4%，其中486个CDS的功能可以确定，92个与假设蛋白质的基因序列匹配，剩下204个CDS在数据库中无显著匹配。该基因组包含一组rRNA基因和仅29个tRNA基因。通过序列分析和使用G + C偏斜方法确定了复制起点oriC。重复核苷酸序列内的序列多态性产生相位可变蛋白抗原，而一个重组酶基因可能催化主要肺支原体表面抗原中的位点特异性DNA倒位。此外，溶血素、分泌型核酸酶和糖蛋白酶被预测为毒力因子。令人惊讶的是，尽管肺支原体基因组比目前已完全测序的其他支原体基因组大，但先前报道的一些对于自我复制的最小细胞必不可少的基因在肺支原体基因组中缺失。
