title: Learning epigenetic regulation from mycobacteria.
abstract: In a eukaryotic cell, the transcriptional fate of a gene is determined by the profile of the epigenetic modifications it is associated with and the conformation it adopts within the chromatin. Therefore, the function that a cell performs is dictated by the sum total of the chromatin organization and the associated epigenetic modifications of each individual gene in the genome (epigenome). As the function of a cell during development and differentiation is determined by its microenvironment, any factor that can alter this microenvironment should be able to alter the epigenome of a cell. In the study published in Nature Communications (Yaseen 2015 Nature Communications 6:8922 doi: 10.1038/ncomms9922), we show that pathogenicMycobacterium tuberculosishas evolved strategies to exploit this pliability of the host epigenome for its own survival. We describe the identification of a methyltransferase fromM. tuberculosisthat functions to modulate the host epigenome by methylating a novel, non-canonical arginine, H3R42 in histone H3. In another study, we showed that the mycobacterial protein Rv2966c methylates cytosines present in non-CpG context within host genomic DNA upon infection. Proteins with ability to directly methylate host histones H3 at a novel lysine residue (H3K14) has also been identified fromLegionella pnemophilia(RomA). All these studies indicate the use of non-canonical epigenetic mechanisms by pathogenic bacteria to hijack the host transcriptional machinery.
authors.affiliation: Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Khosla
authors.affiliation: Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India. ; Graduate Studies, Manipal University, Manipal, India.
authors.forename: Garima
authors.initials: G
authors.lastname: Sharma
authors.affiliation: Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India. ; Graduate Studies, Manipal University, Manipal, India.
authors.forename: Imtiyaz
authors.initials: I
authors.lastname: Yaseen
keywords: DNA methylation; H3R42; Mycobacterium tuberculosis; Rv1988; Rv2966c; epigenetics; histone arginine methylation