Josephine E. Clark-Curtiss, PhD

Josephine E. Clark-Curtiss, PhD
Professor of Medicine
Division of Infectious Diseases and Global Medicine, Department of Medicine

Emerging Pathogens Institute
2055 Mowry Rd.
Gainesville, FL 32611
Office: Rm 258
Lab: 222A & 224

Curtiss-Clark Curtiss Labs






B.S. Biology St. Mary’s College, Notre Dame, IN
Ph.D. Microbiology Medical College of Georgia, Augusta, GA


 Dr. Clark-Curtiss initiated her research career during her Ph.D. studies at the Medical College of Georgia, Augusta, GA. She then joined the research group of Roy Curtiss III at the University of Alabama at Birmingham for postdoctoral studies, initially analyzing the genetic bases for transfer of antibiotic resistance (R) plasmids among enterobacteria. With the inception of recombinant DNA technology, she became part of the Curtiss research team that constructed and characterized the first biologically contained “safe” strains c1776 and DP50 of Escherichia coli that, for a time, were the only approved bacterial strains with which investigators throughout the US could conduct recombinant DNA research in the late 1970s. Dr. Clark-Curtiss subsequently utilized recombinant DNA techniques to conduct research on mycobacteria, beginning in the early 1980s, when she and her colleagues constructed the first recombinant DNA libraries of any mycobacterial strain, thereby initiating molecular genetics research on Mycobacterium leprae and later, on M. tuberculosis and M. avium. Dr. Clark-Curtiss and her research group were among the first to identify specific genes that encoded M. leprae proteins and they were the first to demonstrate the presence of a repeated DNA sequence in the chromosome of M. leprae (now known as Rlep, which is used for the diagnosis of leprosy). Using restriction fragment length polymorphism (RFLP) analyses of genomes from M. leprae isolates from all over the world, Dr. Clark-Curtiss showed that the M. leprae genome is remarkably stable genetically. Dr. Clark-Curtiss’ research group was the first to identify genes encoding antigens of M. leprae that were recognized by antibodies in the sera of leprosy patients.

Dr. Clark-Curtiss has had a long-standing interest in understanding the mechanisms whereby pathogenic mycobacteria, particularly M. tuberculosis and M. avium, are able to survive and grow in human macrophages, an attribute essential for the pathogenesis of these bacteria. Thus, she and members of her research group developed methods to identify genes expressed by M. avium and M. tuberculosis at different time points after infection of primary human macrophages in culture. Using these methods (Subtractive RNA Hybridization and Selective Capture of Transcribed Sequences [SCOTS]), the Clark-Curtiss group were the first to identify genes from small numbers of mycobacteria in the macrophages in an unbiased way (i.e., without relying on RT-PCR using primers for specific genes), well before the development of microarray technology. In addition to gene expression per se, Dr. Clark-Curtiss has also endeavored to understand some of the mechanisms whereby M. tuberculosis regulates gene expression. During the past 10 years, the Clark-Curtiss research group has conducted studies analyzing regulation of gene expression in M. tuberculosis by four different two-component regulatory systems (TcrRS, PrrAB, DevRS and NarLS) and other transcriptional regulators (the eukaryotic serine-threonine protein kinase PknK and the M. tuberculosis Rel toxin-antitoxin modules) and deciphering the roles of these regulatory systems in host-pathogen interactions. The genes encoding the PrrAB two-component regulatory system were identified during the SCOTS analyses and were subsequently shown to essential for the viability of M. tuberculosis. The PknK serine-threonine protein kinase was shown to be a global regulator of protein synthesis and to play a significant role in regulation of the growth rate of M. tuberculosis.

In collaboration with Roy Curtiss III, the Clark-Curtiss group is developing a safe, efficacious vaccine to protect humans against infections by M. tuberculosis, using recombinant, attenuated Salmonella vaccine (RASV) strains to deliver M. tuberculosis protective antigens. The RASV strains are engineered to behave like wild type Salmonella as they traverse the mammalian gastrointestinal tract after oral inoculation, but then, using regulated delayed technologies, to begin synthesizing the antigens after the RASVs have colonized internal lymphoid tissues. The RASVs are also engineered to undergo regulated delayed lysis in vivo, to preclude long-term colonization of the immunized host and to release the synthesized antigens into the cytosol of the host cells, to elicit both humoral (antibody) and cell-mediated immune responses. Several of the RASV-M. tuberculosis constructs provide protection in mice against aerosol challenges with virulent M. tuberculosis that is equivalent to or slightly better than that conferred by M. bovis BCG, which is regarded as the “gold standard” for vaccines against M. tuberculosis. The Clark-Curtiss research group is continuing to improve the RASV and is also analyzing the protective capabilities of nine other M. tuberculosis antigens for possible incorporation into candidate RASV-M. tuberculosis constructs.


  • Graham, J.E., and J.E. Clark-Curtiss.  1999.  Identification of Mycobacterium tuberculosis RNAs synthesized in response to phagocytosis by human macrophages by selective capture of transcribed sequences (SCOTS).  Proc. Natl. Acad. Sci. USA 96: 11554-11559. PMID: 10500215.
  • Hou, J.Y., J.E. Graham, and J.E. Clark-Curtiss.  2002.  Gene expression in Mycobacterium avium during growth in human macrophages.  Infect. Immun. 70: 3714-3726. PMID: 12065514.
  • Haydel, S.E. and J.E. Clark-Curtiss.  2004. Global analysis of two-component system regulator genes during Mycobacterium tuberculosis growth in human macrophages. FEMS Microbiol. Lett. 236: 336-342. PMID: 15251217.
  • Haydel, S.E. and J.E. Clark-Curtiss.  2006.  The Mycobacterium tuberculosis TrcR response regulator represses the expression of a seven-bladed ß-propeller protein.  J. Bacteriol. 188: 150-159. PMID: 16352831.
  • Haydel, S.E., V. Malhotra, G.L. Cornelison and J.E. Clark-Curtiss. 2012. The PrrAB two-component system is essential for Mycobacterium tuberculosis viability and is induced under nitrogen-limiting conditions.  J. Bacteriol. 194: 354-361. PMID: 22081401.
  • Malhotra, V., B.P. Okon and J.E. Clark-Curtiss. 2012. Mycobacterium tuberculosis protein kinase K enables growth adaptation through translation control. J. Bacteriol. 194: 4184-4196. PMID: 22661693.
  • Juarez-Rodriguez, M.D., L.T. Arteaga-Cortes, R. Kader. R. Curtiss III and J.E. Clark-Curtiss. 2012.  Live attenuated Salmonella vaccines against Mycobacterium tuberculosis: Antigen delivery via Type III secretion. Infect. Immun. 80: 798-814. PMID: 22144486.
  • Juarez-Rodriguez, M.D., J. Yang, R. Kader, P. Alamuri, R. Curtiss III and J.E. Clark-Curtiss. 2012. Live attenuated Salmonella vaccine displaying regulated delayed lysis and delayed antigen synthesis to confer protection against Mycobacterium tuberculosis. Infect. Immun. 80: 815-831. PMID: 22144485.
  • Kong, W., M. Brovold, B.A. Koeneman, J.E. Clark-Curtiss and R. Curtiss III. 2012. Turning self-destructing Salmonella into a universal DNA vaccine delivery platform. Proc. Natl. Acad. Sci. USA. 109:19414-19419. PMID: 23129620.
  • Malhotra, V., R. Agarwal, T.R. Duncan, D.K. Saini and J.E. Clark-Curtiss. 2015. Mycobacterium tuberculosis response regulators DevR and NarL interact in vivo and co-regulate gene expression during aerobic nitrate metabolism. J. Biol. Chem. Doi:10.1074/jbc.M114.591800.