d(GC)n repeats form Z-DNA within promoter region and repress the promoter activity in Escherichia coli

摘要

Z-DNA is a left-handed helical form of DNA in which sugarphosphate backbone winds in a zig-zag pattern.DNA containing alternating purine and pyrimidine repeats has the potential to adopt the Z-DNA formation.In vivo,Z-DNA is formed and stabilized by negative supercoil or specific Z-DNA-binding proteins.Z-DNA-forming sequences are widespread in cells,especially in the promoter regions and centromere of chromatins,so it is thought to be involved in some biological processes such as gene expression,genetic instability,and DNA processing events [1].