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 Research Summary
The Genetics of Mycobacterium tuberculosis Virulence
Dr. Smith and his laboratory has been studying the genetics of Mycobacterium tuberculosis virulence to better understand the processes by which the bacterium causes tuberculosis. They are using two major approaches. The first is a novel genetic screen or "promoter trap" that selects for M. tuberculosis genes that are more active during infection. They have found approximately 50 M. tuberculosis genes that are more active when the bacterium infects macrophages - the cells in the human body that protect against infection - and approximately 60 others in the lungs of infected mice. Among the genes they identified are several that are involved in fatty acid metabolism. The lab is currently making M. tuberculosis strains with mutations in some of these genes to ascertain their role in virulence, as well as isolating more genes by the promoter trap technique.
Their second approach uses the published M. tuberculosis genome database to identify and characterize proteins that are expected to be important for virulence based on their similarity to known virulence determinants in other bacterial pathogens. They have studied three main classes of bacterial regulatory proteins, ie, sigma factors, metalloregulators and two-componenet systems and found that inactivation of genes encoding some of these regulatory proteins reduces their virulence in human and mouse macrophages and in mice. Dr. Smith and the members of his laboratory are now studying which genes controlled by the regulatory proteins are essential for M. tuberculosis virulence. In the upcoming years they expect to identify potential targets that will be used to develop new strategies for the diagnosis and treatment of tuberculosis.
Current Year Lab Report
The Smith laboratory is currently trying to ascertain the biochemical function of some of the genes they have been studying that encode enzymes involved in fatty acid metabolism. The group is also trying to understand the regulation of these genes during the infectious process. The team has inactivated a total of 40 M. tuberculosis genes and has tested the virulence of approximately 30, in macrophages and/or mice. Some of these, e.g., sigE, and phoP, encoding transcriptional regulators, are essential for virulence in both systems. Using cutting edge technology such as molecular beacons and DNA arrays, they are finding those genes controlled by the 2 regulators during infections. The group is also continuing studies on the IdeR protein, the major regulator of iron metabolism in M. tuberculosis. This protein is essential and current studies are developing this protein and the gene that encodes it as a potential target for anti-tubercular therapies.
Recent Articles
Giacomini, E., Sotolongo, A., Iona, E., Severa, M., Remoli, M. E., Gafa, V., Lande, R., Fattorini, L., Smith, I., Manganelli, R., Coccia, E. M. (2006).
Infection of Human Dendritic Cells with a Mycobacterium tuberculosis sigE Mutant Stimulates Production of High Levels of Interleukin-10 but Low Levels of CXCL10: Impact on the T-Cell Response.
Infection and Immunity 71: 3296-3304, 2006.
Walters, S., Dubnau, E., Kolesnikova, I, Daffe, M. and Smith I. (2006).
The Mycobacterium tuberculosis PhoP-PhoR two-component system: a regulatory system controlling genes essential for virulence and complex lipid biosynthesis.
Molecular Microbiology 60: 312-330, 2006
Rodriguez, G. M. and Smith, I. (2006).
Identification of an ABC transporter required for iron acquisition and virulence in Mycobacterium tuberculosis.
Jour. Bacteriol. 188: 424-430, 2006
Dainese, E., Rodrigue, S., Delogu, G., Provvedi, R., Laflamme, L., Brzezinski, R.,Fadda, G., Smith, I., Gaudreau, L., Palu, G., & Manganelli, R. (2006).
Mycobacterium tuberculosis ECF sigma factor sL: post-translational regulation, role in virulence and in global regulation of gene expression.
Infection and Immunity 74:2457-246, 2006
Dubnau, E., Chan, J., Mohan, V. P., and Smith, I. (2005)
Responses of Mycobacterium tuberculosis to growth in the Mouse Lung.
Infection and Immunity 73: 3754-3757, 2005
Mendelson, M., Walters, S., , Smith, I., and Kaplan, G. (2005)
Strain specific mycobacterial lipids and the stimulation of protective immunity to tuberculosis.
Tuberculosis 85: 407-413. 2005
Manganelli R, Fattorini L, Tan D, Iona E, Orefici G, Altavilla G, Cusatelli P, Smith I. (2004).
The extra cytoplasmic function sigma factor sigma(E) is essential for Mycobacterium tuberculosis virulence in mice.
Infect Immun. 2004 May;72(5):3038-41
PMID: 15102817
Abstract | Full Article
Manganelli R, Proveddi R, Rodrigue S, Beaucher J, Gaudreau L, Smith I. (2004).
Sigma factors and global gene regulation in Mycobacterium tuberculosis.
J Bacteriol. 2004 Feb;186(4):895-902
PMID: 14761983
Abstract | Full Article
Timm J, Post FA, Bekker LG, Walther GB, Wainwright HC, Manganelli R, Chan WT, Tsenova L, Gold B, Smith I, Kaplan G, McKinney JD. (2003).
Differential expression of iron-, carbon-, and oxygen-responsive mycobacterial genes in the lungs of chronically infected mice and tuberculosis patients.
Proc Natl Acad Sci U S A. 2003 Nov 25;100(24):14321-6. Epub 2003 Nov 17
PMID: 14623960
Abstract
Smith I. (2003).
Mycobacterium tuberculosis pathogenesis and molecular determinants of virulence.
Clin Microbiol Rev. 2003 Jul;16(3):463-96
PMID: 12857778
Abstract | Full Article
Dubnau E, Smith I. (2003).
Mycobacterium tuberculosis gene expression in macrophages.
Microbes Infect. 2003 Jun;5(7):629-37
PMID: 12787739
Abstract | Full Article
Rodriguez, G. M., and Smith, I. (2003).
Mechanisms of iron regulation in mycobacteria: role in physiology and virulence.
Mol Microbiol 2003 Mar;47(6):1485-94
PMID: 12622807
Abstract | Full Article
Beaucher, J., Roderigue, S., Jacques, P.-E., Smith, I., Brzezinski, R and Gaudreau, L. (2002).
Novel Mycobacterium tuberculosis anti-sigma factor antagonists control sigmaF activity by distinct mechanisms.
Mol Microbiol 2002 Sep;45(6):1527-40
PMID: 9593946
Abstract | Full Article
Manganelli R, Voskuil MI, Schoolnik GK, Dubnau E, Gomez M, Smith I. (2002).
Role of the extracytoplasmic-function sigma Factor sigmaH in Mycobacterium tuberculosis global gene expression.
Mol Microbiol 2002 Jul;45(2):365-74
PMID: 12123450
Abstract | Full Article
Rodriguez GM, Voskuil MI, Gold B, Schoolnik GK, Smith I. (2002).
IdeR is an essential gene in mycobacterium tuberculosis: role of IdeR in iron-dependent gene expression, iron metabolism, and oxidative stress response.
Infect Immun 2002 Jul;70(7):3371-81
PMID: 12065475
Abstract | Full Article
Dubnau E, Fontan P, Manganelli R, Soares-Appel S, Smith I. (2002).
Mycobacterium tuberculosis genes induced during infection of human macrophages.
Infect Immun 2002 Jun;70(6):2787-95
PMID: 12010964
Abstract | Full Article
Gold B, Rodriguez GM, Marras SA, Pentecost M, Smith I. (2001).
The Mycobacterium tuberculosis IdeR is a dual functional regulator that controls transcription of genes involved in iron acquisition, iron storage and survivalin macrophages.
Mol Microbiol 2001 Nov;42(3):851-65
PMID: 11722747
Abstract | Full Article
Manganelli R, Voskuil MI, Schoolnik GK, Smith I. (2001).
The Mycobacterium tuberculosis ECF sigma factor sigmaE: role in global geneexpression and survival in macrophages.
Mol Microbiol 2001 Jul;41(2):423-37
PMID: 11489128
Abstract | Full Article
Complete TB Bibliography (Since 1995)
Predich M, Doukhan L, Nair G, Smith I. (1995).
Characterization of RNA polymerase and two sigma-factor genes from Mycobacterium smegmatis.
Mol Microbiol. 1995 Jan;15(2):355-66
PMID: 7746156
Abstract
Doukhan L, Predich M, Nair G, Dussurget O, Mandic-Mulec I, Cole ST, Smith DR, Smith I. (1995).
Genomic organization of the mycobacterial sigma gene cluster.
Gene. 1995 Nov 7;165(1):67-70
PMID: 7489918
Abstract | Full Article
Schmitt MP, Predich M, Doukhan L, Smith I, Holmes RK. (1995).
Characterization of an iron-dependent regulatory protein (IdeR) of Mycobacterium tuberculosis as a functional homolog of the diphtheria toxin repressor (DtxR) from Corynebacterium diphtheriae.
Infect Immun. 1995 Nov;63(11):4284-9 Erratum in: Infect Immun. 1996 Feb;64(2):681
PMID: 7591059
Abstract | Full Article
Dussurget O, Rodriguez M, Smith I. (1996).
An ideR mutant of Mycobacterium smegmatis has derepressed siderophore production and an altered oxidative-stress response.
Mol Microbiol. 1996 Nov;22(3):535-44
PMID: 8939436
Abstract
Gomez M, Doukhan L, Nair G, Smith I. (1998).
sigA is an essential gene in Mycobacterium smegmatis.
Mol Microbiol. 1998 Jul;29(2):617-28
PMID: 9720877
Abstract
Dussurget O, Rodriguez M, Smith I. (1998).
Protective role of the Mycobacterium smegmatis IdeR against reactive oxygen species and isoniazid toxicity.
Tuber Lung Dis. 1998;79(2):99-106
PMID: 10645447
Abstract | Full Article
Smith I, Dussurget O, Rodriguez GM, Timm J, Gomez M, Dubnau J, Gold B, Manganelli R. (1998).
Extra and intracellular expression of Mycobacterium tuberculosis genes.
Tuber Lung Dis. 1998;79(2):91-7
PMID: 10645446
Abstract | Full Article
Dubnau E, Marrakchi H, Smith I, Daffe M, Quemard A. (1998).
Mutations in the cmaB gene are responsible for the absence of methoxymycolic acid in Mycobacterium bovis BCG Pasteur.
Mol Microbiol. 1998 Sep;29(6):1526-8
PMID: 9781890
Manganelli R, Dubnau E, Tyagi S, Kramer FR, Smith I. (1999).
Differential expression of 10 sigma factor genes in Mycobacterium tuberculosis.
Mol Microbiol. 1999 Jan;31(2):715-24
PMID: 10027986
Abstract
Dussurget O, Timm J, Gomez M, Gold B, Yu S, Sabol SZ, Holmes RK, Jacobs WR Jr, Smith I. (1999).
Transcriptional control of the iron-responsive fxbA gene by the mycobacterial regulator IdeR.
J Bacteriol. 1999 Jun;181(11):3402-8
PMID: 10348851
Abstract | Full Article
Rodriguez GM, Gold B, Gomez M, Dussurget O, Smith I. (1999).
Identification and characterization of two divergently transcribed iron regulated genes in Mycobacterium tuberculosis.
Tuber Lung Dis. 1999;79(5):287-98 Erratum in: Tuber Lung Dis 1999;79(6):382
PMID: 10707257
Abstract | Full Article
Dubnau E, Chan J, Raynaud C, Mohan VP, Laneelle MA, Yu K, Quemard A, Smith I, Daffe M. (2000).
Oxygenated mycolic acids are necessary for virulence of Mycobacterium tuberculosis in mice.
Mol Microbiol. 2000 May;36(3):630-7
PMID: 10844652
Abstract
Manganelli R, Voskuil MI, Schoolnik GK, Smith I. (2001).
The Mycobacterium tuberculosis ECF sigma factor sigmaE: role in global gene expression and survival in macrophages.
Mol Microbiol. 2001 Jul;41(2):423-37
PMID: 11489128
Abstract | Full Article
Gold B, Rodriguez GM, Marras SA, Pentecost M, Smith I. (2001).
The Mycobacterium tuberculosis IdeR is a dual functional regulator that controls transcription of genes involved in iron acquisition, iron storage and survival in macrophages.
Mol Microbiol. 2001 Nov;42(3):851-65
PMID: 11722747
Abstract | Full Article
Raynaud C, Guilhot C, Rauzier J, Bordat Y, Pelicic V, Manganelli R, Smith I, Gicquel B, Jackson M. (2002).
Phospholipases C are involved in the virulence of Mycobacterium tuberculosis.
Mol Microbiol. 2002 Jul;45(1):203-17
PMID: 12100560
Abstract | Full Article
Beaucher J, Rodrigue S, Jacques PE, Smith I, Brzezinski R, Gaudreau L. (2002).
Novel Mycobacterium tuberculosis anti-sigma factor antagonists control sigmaF activity by distinct mechanisms.
Mol Microbiol. 2002 Sep;45(6):1527-40
PMID: 9593946
Abstract | Full Article
Manganelli R, Voskuil MI, Schoolnik GK, Dubnau E, Gomez M, Smith I. (2002).
Role of the extracytoplasmic-function sigma factor sigma(H) in Mycobacterium tuberculosis global gene expression.
Mol Microbiol. 2002 Jul;45(2):365-74
PMID: 12123450
Abstract | Full Article
Dubnau E, Fontan P, Manganelli R, Soares-Appel S, Smith I. (2002).
Mycobacterium tuberculosis genes induced during infection of human macrophages.
Infect Immun. 2002 Jun;70(6):2787-95
PMID: 12010964
Abstract | Full Article
Rodriguez GM, Voskuil MI, Gold B, Schoolnik GK, Smith I. (2002).
ideR, An essential gene in mycobacterium tuberculosis: role of IdeR in iron-dependent gene expression, iron metabolism, and oxidative stress response.
Infect Immun. 2002 Jul;70(7):3371-81
PMID: 12065475
Abstract | Full Article
Timm J, Post FA, Bekker LG, Walther GB, Wainwright HC, Manganelli R, Chan WT, Tsenova L, Gold B, Smith I, Kaplan G, McKinney JD. (2003).
Differential expression of iron-, carbon-, and oxygen-responsive mycobacterial genes in the lungs of chronically infected mice and tuberculosis patients.
Proc Natl Acad Sci U S A. 2003 Nov 25;100(24):14321-6. Epub 2003 Nov 17
PMID: 14623960
Abstract
Manganelli R, Fattorini L, Tan D, Iona E, Orefici G, Altavilla G, Cusatelli P, Smith I. (2004).
The extra cytoplasmic function sigma factor sigma(E) is essential for Mycobacterium tuberculosis virulence in mice.
Infect Immun. 2004 May;72(5):3038-41
PMID: 15102817
Abstract | Full Article
Dubnau, E., Chan, J., Mohan, V. P., and Smith, I. (2005).
Responses of Mycobacterium tuberculosis to growth in the Mouse Lung.
Infection and Immunity 73: 3754-3757, 2005
Mendelson, M., Walters, S., , Smith, I., and Kaplan, G. (2005).
Strain specific mycobacterial lipids and the stimulation of protective immunity to tuberculosis.
Tuberculosis 85: 407-413. 2005
Rodriguez, G. M. and Smith, I. (2006).
Identification of an ABC transporter required for iron acquisition and virulence in Mycobacterium tuberculosis.
Jour. Bacteriol. 188: 424-430, 2006
Dainese, E., Rodrigue, S., Delogu, G., Provvedi, R., Laflamme, L., Brzezinski, R.,Fadda, G., Smith, I., Gaudreau, L., Palu, G., & Manganelli, R. (2006).
Mycobacterium tuberculosis ECF sigma factor sL: post-translational regulation, role in virulence and in global regulation of gene expression.
Infection and Immunity 74:2457-246, 2006
Walters, S., Dubnau, E., Kolesnikova, I, Daffe, M. and Smith I. (2006).
The Mycobacterium tuberculosis PhoP-PhoR two-component system: a regulatory system controlling genes essential for virulence and complex lipid biosynthesis.
Molecular Microbiology 60: 312-330, 2006
Book Chapters and Reviews on Tuberculosis
Smith, I., Nathan, C. Peavey, H.H. (2005).
Progress and new Directions in Genetics of Tuberculosis, An NHLBI working group report.
Amer. Jour. Respir. and Crit. Care Med. 172: 1491-1496, 2005
Smith, I., Bishai, W., and Nagaraja, V.(2004).
Control of mycobacterial transcription.
pp. 219-231, in Tuberculosis and the Tubercle Bacillus. (eds. S. Cole, K. D. Eisenach, D. N. McMurray, and W. Jacobs) ASM Press, 2004
Manganelli R, Proveddi R, Rodrigue S, Beaucher J, Gaudreau L, Smith I. (2004).
Sigma factors and global gene regulation in Mycobacterium tuberculosis.
J Bacteriol. 2004 Feb;186(4):895-902
Fontan, P., Walters, S.., and Smith I. (2004).
Cellular signaling pathways and transcriptional regulation in Mycobacterium tuberculosis.
Current Science 86: 122-134, 2004
Rodriguez, G. M., and Smith, I. (2004).
Iron metabolism in pathogenic mycobacteria.
pp. 360-371, in 'Iron Transport in Bacteria: Molecular Genetics, Biochemistry, Microbial Pathogenesis and Ecology', (Eds. J. H. Crosa, A. R. Mey and S. M. Payne) ASM Press, 2004
Dubnau, E., and Smith, I. (2003).
Mycobacterium tuberculosis gene expression in macrophages.
Microbes and Infection 2003 Jun;5(7):629-37
Smith, I. (2003).
Mycobacterium tuberculosis Virulence: A Genetic Analysis.
pp.135-161 in "Tuberculosis, 2nd Ed." (ed W.N.Rom and S. Garay) Lippincot
Smith, I. (2003).
Mycobacterium tuberculosis Pathogenesis and Molecular Determinants of Virulence.
Clinical Microbiological reviews 2003 Jul; 16(3):463-496
Rodriguez, G. M., and Smith, I. (2003).
Role of iron regulation in mycobacterial physiology and virulence.
Molecul. Microbiol. 47: 1485-1494, 2003.
Manganelli, R., Tyagi, S., and Smith, I. (2001).
Real time PCR using molecular beacons: a new tool to discover point mutations and to analyze gene expression in Mycobacterium tuberculosis.
pp. 295-310, in Mycobacterium tuberculosis Protocols, edited by T. Parish and N. G. Stoker, Humana 2001.
Gomez, M. and Smith, I. (2000).
Determinants of gene expression.
pp. 111-129, in "Molecular genetics of Mycobacteria", edited by G. Hatfull and W. Jacobs, ASM Press, 2000.
Timm, J., Gomez, M. and Smith, I. (1999).
Gene expression in mycobacteria.
pp. 59-92, in "Mycobacteria: molecular biology and virulence", edited by J. Dales and C. Ratledge, Chapman and Hall, 1999.
Smith, I. Dussurget, O., Rodriguez, G. M., Timm, J., Gomez, M., Dubnau, J., Gold, M. and Manganelli, R. (1998).
Extra- and intracellular expression of Mycobacterium tuberculosis genes.
Tubercule and Lung Disease 79: 91-97, 1998.
Dussurget, O. and Smith, I. (1998).
Interdependence of mycobacterial iron regulation, oxidative stress and INH resistance.
Trends in Microbiology 6: 354-358, 1998.
C.V.
Education
City College of New York, New York City, B.A., 1955; Columbia University, New York City, M.A., 1957 (Developmental Biology), Ph.D., 1961 (Developmental Biology).
Research Experience
Sloan Kettering Institute for Cancer Research, Post Doc., 1961-1962; New York University School of Medicine (Dept. of Microbiology), Post Doc., 1962-1963; Albert Einstein College of Medicine, Post Doc, 1963-1968; Research Assistant Professor (Dept. of Pathology) 1964-1967; New York University School of Medicine (Dept. of Microbiology), Research Assistant Professor, 1967 - 1980, Research Professor, 1980 Ð2004, Adjunct Professor of Medicine 2004-present; University of Medicine and Dentistry, New Jersey Medical School, Professor (Dept. of Medicine); PHRI (Dept. Of Microbiology 1967-1993, TB Center 1994-Present), Associate, 1967-1973, Associate Member, 1973-1980, Member, 1980-present.
Professional Experience
N.I.H. Study Sections: Microbial Physiology & Genetics, I., Member, 1986-1990; Prokaryotic Molecular biology, 2006-1008, Editorial Board, Journal of Bacteriology, Member, 1975-1993; Molecular Microbiology 1995-present, Board of Directors, International Spores Conference, Inc., President, 1984-1988; Organizing & Program Committees, 10th Intl. Spores Conference, Chairman, 1988; Board of Directors, International Spores Conference, Inc., Member, 1980-1992; 1st, 2nd and 3rd N.Y.C. TB Conferences (1996, 1998. 2000), Organizer; Public Health Research Institute Symposia on Infectious Diseases, Newark, NJ, 2002-2004 Organizer; Tuberculosis Meeting, April, 1998, Keystone, CO., Chairman and Speaker, 1998; 31st -36th US/Japan TB/Leprosy Research Conferences, Nagasaki, Cleveland, Osaka, San Francisco, Yokohama, New Orleans, 1996-2001, Invited Speaker,; TB Symposium ASM General Meeting, Atlanta, Los Angeles, Chairman, Organizer, Speaker 1998, 2000; ASM General Meeting, Washington, D.C., TB Symposium speaker, 2003. Keystone TB meeting 2007, Co-organizer, Chairman, Division U (mycobacteriology) American Society of Microbiology 2006-2007.
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