Coordinate cell cycle control of a Caulobacter DNA methyltransferase and the flagellar genetic hierarchy.

AUTOR(ES)

Stephens, C M

RESUMO

The expression of the Caulobacter ccrM gene and the activity of its product, the M.Ccr II DNA methyltransferase, are limited to a discrete portion of the cell cycle (G. Zweiger, G. Marczynski, and L. Shapiro, J. Mol. Biol. 235:472-485, 1994). Temporal control of DNA methylation has been shown to be critical for normal development in the dimorphic Caulobacter life cycle. To understand the mechanism by which ccrM expression is regulated during the cell cycle, we have identified and characterized the ccrM promoter region. We have found that it belongs to an unusual promoter family used by several Caulobacter class II flagellar genes. The expression of these class II genes initiates assembly of the flagellum just prior to activation of the ccrM promoter in the predivisional cell. Mutational analysis of two M.Ccr II methylation sites located 3' to the ccrM promoter suggests that methylation might influence the temporally controlled inactivation of ccrM transcription. An additional parallel between the ccrM and class II flagellar promoters is that their transcription responds to a cell cycle DNA replication checkpoint. We propose that a common regulatory system coordinates the expression of functionally diverse genes during the Caulobacter cell cycle.

Documentos Relacionados

• Negative transcriptional regulation in the Caulobacter flagellar hierarchy.
• A cell cycle-regulated adenine DNA methyltransferase from Caulobacter crescentus processively methylates GANTC sites on hemimethylated DNA
• Genetic switching in the flagellar gene hierarchy of Caulobacter requires negative as well as positive regulation of transcription.
• Cell cycle-controlled proteolysis of a flagellar motor protein that is asymmetrically distributed in the Caulobacter predivisional cell.
• Expression of Caulobacter dnaA as a function of the cell cycle.