Journal: Frontiers in Public Health
Article Title: Epigenetic Influence of Dam Methylation on Gene Expression and Attachment in Uropathogenic Escherichia coli
Figure Lengend Snippet: Genotypic and growth characteristics displayed by parental and dam- mutant strains of UPEC . (A) Schematic diagram of gene disruption strategy for chromosomal insertion of chloramphenicol resistance gene from pKD3 into dam gene within UPEC chromosome subsequent to λ red recombineering with pKM208. (B) Amplified dam fragment from wild type UPEC strains CFT073 (lane 1) and cured parental strains C119 (lane 2) to produce 1071 bp amplicon. MW is 1 kb DNA ladder (Bioneer Corporation, Republic of Korea) and −ve is negative control. (C) PCR screening of UPEC candidates for dam mutation observed as 1323 bp products using primers UR427 and UR428. MW is a 1 kb Plus DNA ladder (Invitrogen, USA). (D) Dam methylation pattern in UPEC CFT073 wild type (lanes 1, 2, 8, 9, 14, 15), C119 wild type (lanes 3, 4, 10, 11, 16, 17), and E. coli K-12 substrain MG1655 (5, 12, 18) strains subsequent to digestion with Mbo I, Sau 3AI, and Dpn I. The negative control (7, 13, 19) and 1 kb Plus DNA ladder (MW) are also shown. (E) Dam methylation pattern in UPEC dam mutants CFT073 (lanes 1, 2, 3, 8, 9, 10, 15, 16, 17) and C119 wild-type (lanes 4, 5, 6, 11, 12, 13, 18, 19) subsequent to digestion with Sau 3AI, Mbo I, and Dpn I. The negative control (lanes 7, 14) and 1 kb Plus DNA ladder (MW) are also shown. (F) Growth curve (CFU/milliliter versus time) for UPEC strains CFT073, CFT073 Δ dam , cC119, and cC119 Δ dam .
Article Snippet: Essentially, 0.5 μg of chromosomal and plasmid DNA was digested for 1.5 h at 37°C with 2 U Sau 3AI (Promega, WI, USA), 10 U Dpn I (New England Biolabs, MA, USA), or 2.5 U Mbo I. Sau 3AI cleaves DNA at GATC sites regardless of methylation state, Dpn I cleaves GATC sites that have a methylated adenine residue, and Mbo I cleaves unmethylated GATC sites.
Techniques: Mutagenesis, Amplification, Negative Control, Polymerase Chain Reaction, Methylation