In mammals DNA methylation occurs at position 5 of cytosine in a CpG context and regulates gene expression. It plays an important role in diseases and inhibitors of DNA methyltransferases (DNMTs)--the enzymes responsible for DNA methylation--are used in clinics for cancer therapy. The most potent inhibitors are 5-azacytidine and 5-azadeoxycytidine. Zebularine (1-(beta-D-ribofuranosyl)-2(1H)- py...

To create new, effective reagents for affinity modification of restriction-modification (R-M) enzymes, a regioselective method for reactive dialdehyde group incorporation into oligonucleotides, based on insertion of a 1-beta-D-galactopyranosylthymine residue, has been developed. We synthesized DNA duplex analogs of the substrates of the Eco RII and Mva I R-M enzymes that contained a galactose o...

Bacterial DNA-methyltransferases are responsible for site-specific modification of DNA. They transfer the methyl-group from Sadenosylmethionine (SAM) to DNA with formation of N6-methyladenosine (m6A), 5-methylcytosine (m5C) or N4-methylcytosine (m4Q (1). Lately nucleotide structures of more than one hundred genes of different methyltransferases have been determined (2). Analysis of deduced amin...

Two pairs of restriction enzyme isoschizomers were used to study in vivo methylation of E. coli and extrachromosomal DNA. By use of the restriction enzymes MboI (which cleaves only the unmethylated GATC sequence) and its isoschizomer Sau3A (indifferent to methylated adenine at this sequence), we found that all the GATC sites in E. coli and in extrachromosomal DNAs are symmetrically methylated o...

Genes belonging to different erm DNA hybridization classes were selectively amplified by polymerase chain reaction with a pair of oligonucleotides that corresponded to conserved amino acid motifs in known ERM methylases. Identification of the resistance mechanism was possible despite substantial nucleotide sequence diversity among the erythromycin resistance genes.

Sequence analysis of the BcnI restriction-modification system from Bacillus centrosporus revealed four open reading frames (bcnIC, bcnIR, bcnIB and bcnIA) that are arranged as two converging collinear pairs. One pair encodes a putative small regulatory protein, C.BcnI, and the restriction endonuclease R.BcnI. The other two gene products are the DNA cytosine-N4 methyltransferases M.BcnIA and M.B...

Fifteen carbapenemase-producing Enterobacteriaceae isolates and 12 carbapenemase-producing Pseudomonas aeruginosa isolates were recovered from patients hospitalized between August 2011 and March 2013 at the Hospital of Infectious Disease, Cluj-Napoca, Romania. One KPC-, nine NDM-1-, four OXA-48-, and one VIM-4-producing Enterobacteriaceae isolates along with 11 VIM-2-producing and one IMP-13-pr...