Characterization of the transcriptional regulator Rv3124 of Mycobacterium tuberculosis identifies it as a positive regulator of molybdopterin biosynthesis and defines the functional consequences of a non-synonymous SNP in the Mycobacterium bovis BCG orthologue.
A number of single-nucleotide polymorphisms (SNPs) have been identified in the genome of Mycobacterium bovis BCG Pasteur compared with the sequenced strain M. bovis 2122/97. The functional consequences of many of these mutations remain to be described; however, mutations in genes encoding regulators may be particularly relevant to global phenotypic changes such as loss of virulence, since alteration of a regulator's function will affect the expression of a wide range of genes. One such SNP falls in bcg3145, encoding a member of the AfsR/DnrI/SARP class of global transcriptional regulators, that replaces a highly conserved glutamic acid residue at position 159 (E159G) with glycine in a tetratricopeptide repeat (TPR) located in the bacterial transcriptional activation (BTA) domain of BCG3145. TPR domains are associated with protein-protein interactions, and a conserved core (helices T1-T7) of the BTA domain seems to be required for proper function of SARP-family proteins. Structural modelling predicted that the E159G mutation perturbs the third alpha-helix of the BTA domain and could therefore have functional consequences. The E159G SNP was found to be present in all BCG strains, but absent from virulent M. bovis and Mycobacterium tuberculosis strains. By overexpressing BCG3145 and Rv3124 in BCG and H37Rv and monitoring transcriptome changes using microarrays, we determined that BCG3145/Rv3124 acts as a positive transcriptional regulator of the molybdopterin biosynthesis moa1 locus, and we suggest that rv3124 be renamed moaR1. The SNP in bcg3145 was found to have a subtle effect on the activity of MoaR1, suggesting that this mutation is not a key event in the attenuation of BCG.
Mendoza Lopez
Pablo
P
TB Research Group, VLA Weybridge, New Haw, Surrey KT15 3NB, UK.|Vircell S.L., Pol. Ind. Dos de Octubre, Plaza Domínguez Ortiz 1, 18320 Santa Fé, Granada, Spain.
Golby
Paul
P
TB Research Group, VLA Weybridge, New Haw, Surrey KT15 3NB, UK.
Wooff
Esen
E
TB Research Group, VLA Weybridge, New Haw, Surrey KT15 3NB, UK.
Garcia
Javier Nunez
JN
TB Research Group, VLA Weybridge, New Haw, Surrey KT15 3NB, UK.
Garcia Pelayo
M Carmen
MC
TB Research Group, VLA Weybridge, New Haw, Surrey KT15 3NB, UK.
Conlon
Kevin
K
Agriculture, Food Science and Veterinary Medicine, University College Dublin, Dublin 4, Ireland.
Gema Camacho
Ana
A
Vircell S.L., Pol. Ind. Dos de Octubre, Plaza Domínguez Ortiz 1, 18320 Santa Fé, Granada, Spain.
Hewinson
R Glyn
RG
TB Research Group, VLA Weybridge, New Haw, Surrey KT15 3NB, UK.
Polaina
Julio
J
Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Polígono de la Coma s/n, Paterna, Valencia, 46980, Spain.
Suárez García
Antonio
A
Centro de Investigación Biomédica, Parque Tecnológico Ciencias de la Salud, Avda Conocimiento s/n, 18100 Armilla, Granada, Spain.
Gordon
Stephen V
SV
Biomolecular and Biomedical Science, College of Life Sciences, University College Dublin, Dublin 4, Ireland.|Medicine and Medical Science, University College Dublin, Dublin 4, Ireland.|Agriculture, Food Science and Veterinary Medicine, University College Dublin, Dublin 4, Ireland.|TB Research Group, VLA Weybridge, New Haw, Surrey KT15 3NB, UK.|UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland.
D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003067:Coenzymes / Q000096:biosynthesis* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D008667:Metalloproteins / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D000090006:Molybdenum Cofactors; D009163:Mycobacterium bovis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D011621:Pteridines; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D003067:Coenzymes; D008667:Metalloproteins; D000090006:Molybdenum Cofactors; D011621:Pteridines; D014157:Transcription Factors; C022261:molybdopterin