DNA enzyme generated by a novel single-stranded DNA expression vector inhibits expression of the essential bacterial cell division gene ftsZ.

Rapid emergence of antibiotic-resistant bacterial pathogens has created urgent demand for the discovery and development of new antibacterial agents directed toward novel targets. Antisense oligodeoxynucleotides (AS-ODN) and their modified forms have been utilized to block gene expression in bacterial cells, showing potential for developing highly specific and efficacious antibacterial agents. In this study, a tetracycline-regulated expression vector was developed for generating single-stranded DNA (ssDNA) of a desired target sequence in bacterial cells. This inducible ssDNA expression vector was tested for producing a DNA enzyme designed to specifically cleave ftsZ mRNA. Our results indicate that the expressed DNA enzyme molecules not only repress ftsZ gene expression and but also inhibit bacterial cell proliferation. Although we believe that the cleavage of ftsZ mRNA by the expressed DNA enzyme molecules is responsible for the inhibitory effects on ftsZ gene expression and bacterial cell proliferation, the antisense mechanism could also be responsible for the biological effects. The ability of this ssDNA expression system to selectively modulate gene expression may provide a powerful strategy in determining the contribution of a given gene product to bacterial growth or pathogenesis and opens a new venue for developing antibacterial agents.