Public Health Research Institute Center
UMDNJ - New Jersey Medical School
225 Warren Street
Newark, New Jersey 07103

Phone: (973) 854-3402
e-mail: hahnje@umdnj.edu


Research Summary

The soil organism Bacillus subtilis has the ability to take up DNA from its environment and, provided there is homology, recombine it into its genome. This process is called transformation. In order for the bacterium to be transformed it must be in a specific physiological state called competence. During the competent state specific proteins are synthesized which are required for the binding and transport of the DNA molecule into the competent cell. It has been found that as transformability increases many competence specific proteins localize to the poles of the rod shaped Bacillus subtilis bacterium and as transformability declines the competence proteins delocalize. These proteins colocalize and interact and seem to form a complex that helps internalize the DNA molecule, preferentially at the poles of the cell. Jeanette Hahn’s focus is understanding how the polar localization and delocalization of the competence proteins occurs. Localization seems to occur via a diffusion and capture mechanism whereas delocalization is energy driven and involves degradation of an as yet unknown anchor protein(s). Elucidating the proteins and signals involved in this process is under investigation.


                    

     The late competence protein ComGA, which is required
     for the binding and uptake of transforming DNA, localizes
     to the poles of the competent cell. ComGA is fused to gfp.





Recent Articles

Hahn J, Kramer N, Briley Jr. K, Dubnau D.
McsA and B mediate the delocalization of competence proteins from the cell poles of Bacillus subtilis.
Mol Microbiol. 2009 Apr;72(1):202-15.

Kramer N, Hahn J, Dubnau D.
Multiple Interactions Among Competence Proteins of Bacillus Subtilis.
Mol Microbiol. 2007 July;65(2):454-464.

Hahn J, Maier B, Haijema BJ, Sheetz M, Dubnau D.
Transformation Proteins and DNA Uptake Localize to the Cell Poles in Bacillus subtilis.
Cell.2005, July 122(1): 59-71.

Berka RM, Hahn J, Albano M, Draskovic I, Persuh M, Cui X, Sloma A, Widner W, Dubnau D.
Microarray analysis of the Bacillus subtilis K-state: genome-wide expression changes dependent on ComK.
Mol Microbiol. 2002 Mar;43(5):1331-45.

Turgay K, Persuh M, Hahn J, Dubnau D.
Roles of the two ClpC ATP binding sites in the regulation of competence and the stress response.
Mol Microbiol. 2001 Nov;42(3):717-27.

Haijema BJ, Hahn J, Haynes J, Dubnau D.
ComGA-dependent checkpoint limits growth during the escape from competence.
Mol Microbiol. 2001 Apr;40(1):52-64.

Hahn J, Turgay K, , Burghoorn J, Dubnau D.
Competence in Bacillus subtilis is controlled by regulated proteolysis of a transcription factor.
EMBO J. 1998 Nov 16;17(22):6730-8.

Hahn J, Luttinger A, Dubnau D.
Regulatory inputs for the synthesis of ComK, the competence transcription factor of Bacillus subtilis.
Mol Microbiol. 1996 Aug;21(4):763-75.






C.V.


Education

Ph.D. New York University Medical School. 1982
M.Sc. New York University, 1977
B.Sc. The City University of New York, 1975

Professional Experience

Assistant Professor of Microbiology and Molecular Genetics, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, 2006 – present. Senior Research Associate, Department of Molecular Genetics, Public Health Research Institute, 2000 – present. Research Associate, Department of Molecular Genetics, Public Health Research Institute, 1993 – 2000.