Areas of Interest
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
Taghbalout, A. and Rothfield, L. (2008) RNaseE and RNA Helicase
B Play Central Roles in the Cytoskeletal Organization of the RNA
Degradosome. J Biol Chem. 283:13850-5. Taghbalout, A. and
Rothfield, L. (2007) RNaseE and the other constituents of the
RNA degradosome are components of the bacterial cytoskeleton.
Proc. Natl. Acad. Sci. USA, 104:1667-1672
Vats, P. and Rothfield, L. (2007) Duplication and segregation
of the actin (MreB) cytoskeleton during the prokaryotic cell
cycle Proc. Natl. Acad. Sci. USA, 104: 17,795-17,800.
Rothfield, L., Taghbalout, A. and Shih, Y-L (2005) Spatial
control of bacterial division site placement. Nature
Microbiology Reviews. 3:959-967. Shih, Y-L, Le, T., and
Rothfield, L. I. (2003) Division site selection in Escherichia
coli involves dynamic redistribution of Min proteins within
coiled structures that extend between the two cell poles. Proc.
Natl. Acad. Sci. U.S.,100:7865-7870.
Commentary article- Gitai and Shapiro (2003) Proc. Natl.
Acad. Sci. U.S. 100:7423-7424. Fu, X., Shih, Y-L, Zhang, Y.,
and Rothfield, L. (2001). The MinE ring required for proper
placement of the division site is a mobile structure that
changes its cellular location during the E. coli division cycle.
Proc. Natl. Acad. Sci. U.S. .98:980-985.
Commentary article- RayChaudhuri et al (2001) Proc. Natl.
Acad. Sci. U.S. 98:1332-1334.
King, G.F., Shih, Y-L., Maciewiejewski, M.W., Bains, N., Pan,
B., Rowland, S., Mullen, G., and Rothfield, L. (2000) Structural
basis for the topological specificity function of MinE. Nature
Struct. Biol., 7:1013-1017.
News and Views article- RayChaudhuri et al (2000) Nature
Struct. Biol. 7:997-999. rev. 3/09 |
