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Coordinate Cell Cycle Control Of A Caulobacter Dna Methyltransferase And The Flagellar Genetic Hierarchy, Craig Stephens, Gary Zweiger, Lucy Shapiro
Coordinate Cell Cycle Control Of A Caulobacter Dna Methyltransferase And The Flagellar Genetic Hierarchy, Craig Stephens, Gary Zweiger, Lucy Shapiro
Biology
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 …
A Cell Cycle-Regulated Bacterial Dna Methyltransferase Is Essential For Viability, Craig Stephens, Ann Reisenaur, Rachel Wright, Lucy Shapiro
A Cell Cycle-Regulated Bacterial Dna Methyltransferase Is Essential For Viability, Craig Stephens, Ann Reisenaur, Rachel Wright, Lucy Shapiro
Biology
The CcrM adenine DNA methyltransferase, which specifically modifies GANTC sequences, is necessary for viability in Caulobacter crescentus. To our knowledge, this is the first example of an essential prokaryotic DNA methyltransferase that is not part of a DNA restriction/modification system. Homologs of CcrM are widespread in the Cl subdivision of the Proteobacteria, suggesting that methylation at GANTC sites may have important functions in other members of this diverse group as well. Temporal control of DNA methylation state has an important role in Caulobacter development, and we show that this organism utilizes an unusual mechanism for control of remethylation of newly …
Caulobacter Lon Protease Has A Critical Role In Cell-Cvcle Cbntrol Of Dna I Methylation, Craig Stephens, Rachel Wright, Gary Zweiger, Lucy Shapiro, M.R.K. Alley
Caulobacter Lon Protease Has A Critical Role In Cell-Cvcle Cbntrol Of Dna I Methylation, Craig Stephens, Rachel Wright, Gary Zweiger, Lucy Shapiro, M.R.K. Alley
Biology
CcrM, an adenine DNA methyltransferase, is essential for viability in Caulobacter crescentus. The CcrM protein is present only in the predivisional stage of the cell cycle, resulting in cell-cycle-dependent variation of the DNA methylation state of the chromosome. The availability of CcrM is controlled in two ways: (1) the ccrM gene is transcribed only in the predivisional cell, and (2) the CcrM protein is rapidly degraded prior to cell division. We demonstrate here that CcrM is an important target of the Lon protease pathway in C. crescentus. In a lon null mutant, ccrM transcription is still temporally regulated, but the …