DNA replication in bacteria

F. Jacob, S. Brenner, and F. Cuzin, On the regulation of DNA replication in bacteria. Cold Spring Hark Symp. Quant. Biol. 28, 329-342 (1963). 

The Universality of Semiconservative Replication Overview of DNA Replication in Bacteria... 

Related topics DNA replication in bacteria (F3) Transcription in DNA replication in eukaryotes (F4) prokaryotes (G2) RNA structure (Gl) Transcription in eukaryotes an overview (G5)... 

Related topics DNA structure (FI) Nucleic acid hybridization (12) DNA replication in bacteria (F3) DNA cloning (13) Restriction enzymes (11) DNA sequencing (15)... 

Question By what mechanism is the rate of DNA replication in bacteria altered ... 

The elongation phase of DNA replication in bacteria has been seen to involve many enzymes and proteins, and some are associated with discrete functional complexes, such as the DNA polymerase III holoenzyme. Initiation of replication also uses several proteins, and mutations in their genes have been very helpful in identifying these proteins. 

The stages of DNA replication in bacteria are initiation, elongation, and termination. Control of replication is effected at the level of initiation. Thus, the frequency of initiation determines the frequency of completion of cycles of replication. The rate of replication-fork movement (elongation) remains fairly constant under conditions that change the overall rate of replication. There is no evidence to suggest that termination has any control over the rate of replication. 

DNA replication in bacteria is a cyclic process in the sense that at regular time intervals, depending on the richness of the growth medium, initiation of replication is effected at the chromosome origin (oriC). A number of specific proteins and enzymes are directly involved in the initiation of replication, and they are not involved in the subsequent growth of the DNA. Once initiated, a cycle of replication runs to completion in the absence of initiation proteins or enzymes but in the absence of these enzymes and factors, no new cycles start. 

What effect would an inhibitor of RNA polymerase be expected to have on DNA replication in bacteria ... 

Antibiotics, such as ciprofloxacin, that inhibit normal DNA replication in bacteria can be counteracted by the polymerase repair molecules from the SOS response. However, certain polymerases in the SOS pathway are error-prone in their copying of DNA, which leads to mutations. While such mutations are often lethal to the cell, they can also improve the bacteria s survival. 

Eukaryotic cell cycle - The processes by which cells divide and DNA is replicated (see here) are somewhat more complicated in eukaryotes than in prokaryotes. DNA replication in bacteria is an almost continuous process, at least during exponential growth. The somatic cells of eukaryotes, on the other hand, typically divide much less frequently, and some, in certain types of mature tissue, do not divide at all. Eukaryotic cells that are dividing in growing tissues exhibit a well-defined cell cycle, which is almost always separated into several distinct phases, as shown in Figure 28.14, Figure 28.15, and Figure 28.16. 

Along the way as new work is performed on the problems associated with DNA vaccines, technological refinements and innovations will occur in plasmid and host cell design. These developments may have useful spin offs. From a basic standpoint, much more will be learned about how metabolism and its regulation integrates with DNA replication in bacteria such as E. coli. Developing new selection methods for plasmid-containing cells that do not rely on antibiotics will not only comply with FDA... 

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