DnaA protein, the initiator protein for initiation of Escherichia coli chromosomal replication, has been shown to repress its own expression from two dnaA promoters, 1P and 2P. The sequence-specific binding of DnaA protein to the DnaA box, located between the two promoters, results in subsequent oligomerization of DnaA protein. Upon increasing the concentration of DnaA protein, the oligomerization proceeds to both dnaA promoters from the DnaA box and inhibits RNA polymerase binding to both promoters. This results in the repression of transcription, suggesting that the extent of oligomerization of DnaA proteins over two dnaA promoters contributes to the autoregulation of expression of the dnaA gene. When the two dnaA promoters were bound and repressed by DnaA protein, the interaction of RNA polymerase with IciA protein, which is a specific inhibitor of initiation of in vitro E. coli chromosomal replication, appeared to dissociate the oligomerized DnaA proteins from the 1P promoter and allowed RNA polymerase to be loaded for its transcription.
We demonstrate that in mesoscopic type II superconductors with the lateral size commensurate with London penetration depth, the ground state of vortices pinned by homogeneously distributed columnar defects can form a hierarchical nested domain structure. Each domain is characterized by an average nu...
We studied the
Vortex lattice in MgB2 as it was driven from a metastable to the ground state
Through a series of small changes in the applied magnetic field. Our results
Show that metastability in MgB2 is not the result of pinning defects. Rather,
We propose that it is due to the jamming of counter...
Mechanism of self-organization in unbounded, double-species, two-dimensional
(2D) point vortex system is discussed. A kinetic equation is obtained using the
Klimontovich formalism. No axisymmetric flow is assumed. The obtained collision
term consists of a diffusion and a drift term similar to the F...
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