Cellular location of origin and terminus of replication in Bacillus subtilis

Abstract

The origin of replication of Bacillus subtilis 168 trp thy dna-i (temperature-sensitive initiation mutant) was labeled with [3H]thymidine. Analysis of labeled cells by autoradiography revealed that most of the radioactivity was associated with cell pole areas. To label the terminus, cells that had initiated were treated with chloramphenicol to inhibit cell growth and division but to allow continued DNA synthesis. These cells were then labeled with [3H]thymidine at a time when chromosome replication was nearly complete. The distribution of radioactivity was similar to that observed in origin-labeled cells. In contrast, exponentially growing cells that were labeled for a brief time at the permissive temperature showed a random distribution of radioactivity. These data indicate that the origin and terminus of replication are located at cell poles.

To shape a cell: an inquiry into the causes of morphogenesis of microorganisms.

“…The model requires that poles and side walls be formed at different times, and this also appears to be the case. Recent additions are the demonstration that the planar septum cam stretch while splitting, generating two cup-shaped poles despite the presence of enough vancomycin to prevent additional wall synthesis (160); that the terminus and origins of DNA replication are indeed associated with the poles (262); and that new wall is incorporated uniformly rather than in defined zones, as had been thought before (187).…”

The growth strategy of the Gram-positive rod

“…This model is explained in more detail in [23]. It has been modified, in that the location of the origin binding sites is now thought to he more probably at the tips of the poles [25,29].…”