Cell cycle-specific replication of Escherichia coli minichromosomes.

AUTOR(ES)

Leonard, A C

RESUMO

The timing of Escherichia coli minichromosome replication in the cell division cycle was examined using an improved procedure for studying plasmid replication frequency. Cultures growing exponentially in glucose/Casamino acids minimal medium were pulse-labeled with [3H]thymidine, and the radioactivity incorporated into plasmid DNA in cells of different ages was analyzed. At the end of the labeling period the bacteria were bound to the surface of a nitrocellulose membrane filter, and the radioactivity in new daughter cells, which eluted continuously from the membrane, was quantitated following agarose gel electrophoresis. The minichromosomes replicated during a discrete interval in the cell division cycle that appeared to coincide with initiation of chromosome replication. In contrast, plasmid pBR322 replicated throughout the division cycle at a rate that increased gradually as a function of cell age. The difference in minichromosome and pBR322 replication was clearly discernible in cells harboring both plasmids. It was also found that the 16 kD gene adjacent to oriC was not a determinant of the timing of minichromosome replication during the division cycle. The results are consistent with the conclusion that minichromosome replication frequency is governed by the same mechanism that controls chromosome replication.

Documentos Relacionados

• Cell cycle-specific effects of lovastatin.
• Cell Cycle-Specific Incorporation of Lipoprotein into the Outer Membrane of Escherichia coli
• Cell cycle-specific changes in nucleoprotein complexes at a chromosomal replication origin.
• Stability and replication control of Escherichia coli minichromosomes.
• Cell cycle-specific expression and nuclear binding of DNA polymerase alpha.