DNA repair in reduced genome: the Mycoplasma model.

Autor: Carvalho FM; Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, 59072-970, Brazil., Fonseca MM, Batistuzzo De Medeiros S, Scortecci KC, Blaha CA, Agnez-Lima LF
Jazyk: angličtina
Zdroj: Gene [Gene] 2005 Nov 07; Vol. 360 (2), pp. 111-9. Date of Electronic Publication: 2005 Sep 08.
DOI: 10.1016/j.gene.2005.06.012
Abstrakt: The occurrence of bacteria with a reduced genome, such as that found in Mycoplasmas, raises the question as to which genes should be enough to guarantee the genomic stability indispensable for the maintenance of life. The aim of this work was to compare nine Mycoplasma genomes in regard to DNA repair genes. An in silico analysis was done using six Mycoplasma species, whose genomes are accessible at GenBank, and M. synoviae, and two strains of M. hyopneumoniae, whose genomes were recently sequenced by The Brazilian National Genome Project Consortium and Southern Genome Investigation Program (Brazil) respectively. Considering this reduced genome model, our comparative analysis suggests that the DNA integrity necessary for life can be primarily maintained by nucleotide excision repair (NER), which is the only complete repair pathway. Furthermore, some enzymes involved with base excision repair (BER) and recombination are also present and can complement the NER activity. The absence of RecR and RecO-like ORFs was observed only in M. genitalium and M. pneumoniae, which can be involved with the conservation of gene order observed between these two species. We also obtained phylogenetic evidence for the recent acquisition of the ogt gene in M. pulmonis and M. penetrans by a lateral transference event. In general, the presence or nonexistence of repair genes is shared by all species analyzed, suggesting that the loss of the majority of repair genes was an ancestral event, which occurred before the divergence of the Mycoplasma species.
Databáze: MEDLINE
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