The Largest Open Reading Frame (pks12) in the Mycobacterium tuberculosis Genome Is Involved in Pathogenesis and Dimycocerosyl Phthiocerol Synthesis
AUTOR(ES)
Sirakova, Tatiana D.
FONTE
American Society for Microbiology
RESUMO
The cell wall lipids in Mycobacterium tuberculosis are probably involved in pathogenesis. The largest open reading frame in the genome of M. tuberculosis H37Rv, pks12, is unique in that it encodes two sets of domains needed to produce fatty acids. A pks12-disrupted mutant was produced, and disruption was confirmed by both PCR analysis and Southern blotting. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that a 430-kDa protein band present in the wild type was missing in the mutant. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MS) and liquid chromatography (LC)-MS analysis of tryptic peptides showed that 54 peptides distributed throughout this protein matched the pks12-encoded sequence. Biochemical analysis using [1-14C]propionate as the radiotracer showed that the pks12 mutant was deficient in the synthesis of dimycocerosyl phthiocerol (DIM). SDS-PAGE, immunoblot analysis of proteins, and analysis of fatty acids showed that the mutant can produce mycocerosic acids. Thus, the pks12 gene is probably involved in the synthesis of phthiocerol, the diol required for DIM synthesis. Growth of the pks12 mutant was attenuated in mouse alveolar macrophage cell line MH-S, and the virulence of the mutant in vivo was highly attenuated in a murine model. Thus, pks12 probably participates in DIM production and its expression is involved in pathogenesis.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=161999Documentos Relacionados
- Regulation of Expression of mas and fadD28, Two Genes Involved in Production of Dimycocerosyl Phthiocerol, a Virulence Factor of Mycobacterium tuberculosis
- Attenuation of Mycobacterium tuberculosis by Disruption of a mas-Like Gene or a Chalcone Synthase-Like Gene, Which Causes Deficiency in Dimycocerosyl Phthiocerol Synthesis
- Open reading frame cloning: identification, cloning, and expression of open reading frame DNA.
- The regulation of synthesis and properties of the protein product of open reading frame P of the herpes simplex virus 1 genome.
- Hepatitis B virus particles contain a polypeptide encoded by the largest open reading frame: a putative reverse transcriptase.