An orphan DNA (cytosine-5-)-methyltransferase in Vibrio cholerae

Banerjee, Sanjib and Chowdhury, Rukhsana (2006) An orphan DNA (cytosine-5-)-methyltransferase in Vibrio cholerae. Microbiology SGM, 152. pp. 1055-1062.


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    5-Methyl cytosine (m5C) was detected in genomic DNA of the enteric pathogen Vibrio cholerae by HPLC analysis and immunoblotting with m5C-specific antibody. Although cleavage with the restriction endonuclease EcoRII revealed the absence of a Dcm homologue in V. cholerae, analysis of the genome sequence indicated the presence of a gene, designated in this study as vchM, which encodes a DNA (cytosine-5-)-methyltransferase (m5C-MTase) designated M.Vch. M.Vch is not associated with a restriction endonuclease or a mismatch very short patch repair (Vsr)-like endonuclease and is hence an ‘orphan’ or solitary MTase, although analysis of a phylogenetic tree indicated that related cytosine MTases are all components of restriction-modification systems. M.Vch recognizes and methylates the first 59 C in the degenerate sequence 59-RCCGGY-39. RT-PCR analysis suggested that vchM gene expression is increased during the stationary phase of growth. During stationary phase, the spontaneous mutation frequency in the V. cholerae wild-type strain was significantly higher than in the corresponding vchM mutant strain, suggesting that the presence of M.Vch and the absence of a very short patch (VSP) repair-like system imposes upon V. cholerae a mutator phenotype.

    Item Type: Article
    Subjects: Infectious Diseases and Immunology
    Divisions: Indian Institute of Chemical Biology
    Depositing User: Ms Sutapa Ganguly
    Date Deposited: 01 Nov 2011 12:57
    Last Modified: 05 Jan 2016 13:34
    Official URL:

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