|
Faculty
 Lawrence
I. Rothfield
Professor of Microbiology
lroth@panda.uchc.edu
The process of bacterial cell division is being studied to determine
the molecular mechanisms that permit the cell to: (1) identify the
proper location for the division site (normally the midpoint of the
cell); (2) differentiate the division site to permit the subsequent
formation of the division septum; (3) coordinate these events with other
cell cycle events, such as DNA replication and segregation; (4) ensure
that the genome is equally partitioned into the two daughter cells. A
combination of genetic and biochemical approaches are used. Mutants of
E. coli are studied that are blocked in each of these aspects of
the normal division process. These include mutants that place the
division septum near the cell pole, thereby producing small cells (minicells)
that lack chromosomal DNA; mutants that are blocked in various ages of
division due to defects in essential division proteins; and mutants that
fail to equally partition daughter chromosomes into progeny cells.
Biochemical characterization of the mutant cells involves isolation of
the division site within the membrane, and characterization of the
defects resulting from the individual mutations, or from altered levels
of genetic expression of the key genes. Electron and phase contrast
microscopy, usually involving immuno-microscopy, are used to identify
the sites of the mutational blocks and to characterize the aberrant
division organelles that are formed. Cloning and in vitro
manipulation of the relevant genes are carried out to manipulate the
division process and to define the modes of action of the essential cell
division proteins.
Selected Publications:
Rothfield, L. and Justice, S. 1997. Bacterial Cell Division: The
Cycle of the Ring. Cell, 88:581-584.
Sen, M. and Rothfield, L.I. 1998. Stability of the E. coli division
inhibitor protein MinC requires determinants in the carboxy-terminal
region of the protein. J. Bacteriol. 180:175-177.
Shakibai, N., Ishidate, K., Reshetnyak, E., Gunji, S., Kohiyama, M.
and Rothfield, L. 1998. The high affinity binding of hemimethylated oriC
by E. coli membranes is mediated by a multiprotein system that includes
SeqA and a newly identified factor, SeqB. PNAS, 95:11117-11123.
Zhang, Y., Rowland, S., King, G. and L. Rothfield. 1998. Relation of
the oligomeric structure of MinE to its topological specificity
function. Mol. Microbiol., 30:265-273.
Ishidate, K., Ursinus, A., Höltje, J., and Rothfield, L. 1998. Murein
biosynthetic pattern in ftsZ and ftsI mutants of Escherichia coli. FEMS
Microbiol. Lett. 168:71-75.
Cook, W. R. and Rothfield, L. 1999. Nucleoid-independent positioning
of cell division sites in Escherichia coli . J. Bacteriol.
181:1900-1905.
King, G.F., Rowland, S.L., Pan, B, Mackay, J., Mullen, G., and
Rothfield, L.I. 1999. The dimerization and topological specificity
functions of MinE reside in a structurally autonomous C-terminal domain
Molec. Microbiol. 31, 1161-1170.
King, G., Maciejewski, M., Pan, B., Rowland, S., Rothfield, L., and
Mullen, G. P. 1999. Backbone and sidechain 1H, 15N and 13C assignments
for the topological specificity domain of the MinE cell division
protein. J. Biomol. NMR. 13:395-396. |
