Breakdown of the Bacterial Chromosome, Cell Nucleoid, Chromosomal DNA, DNA Polymerase, Bacterial Cell

Breakdown of The Bacterial Chromosome

Breakdown of The Bacterial Chromosome - The bacterial chromosome undergoes breakdown soon after infection. Three types of reactions, unfolding, disruption and degradation, appear to be involved in this breakdown. These reactions appear to be independent processes.

(i) Unfolding. The chromosome undergoes ‘unfolding' and loses its compactness. The unfolding is the result of relaxation of the superhelical twists. T4 unf mutants are defective in the unfolding of the host cell nucleoid.

(ii) Disruption. The centrally located nucleoid is disrupted, and the DNA becomes associated with the membrane at numerous points. T4 add mutants cannot bring about disruption. The add gene product appears to bring about attachment of chromosomal DNA to the bacterial cell membrane at many points. DNA polymerase I may be simultaneously bound to the membrane in this step.

(iii) Degradation. The DNA is cleaved by an endonuclease to small fragments that are further broken down by another nuclease into acid soluble fragments.

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Breakdown of The Bacterial Chromosome