Transcription-dependent DNA supercoiling in yeast DNA topoisomerase mutants

摘要: Studies with yeast DNA topoisomerase mutants indicate that neither I nor II appears to be essential for transcription by RNA polymerase II. However, plasmids carrying transcriptionally active genes are found extremely negatively supercoiled when isolated from lacking I. Supercoiling occurs during transcriptional elongation rather than activation. It takes place in the absence of and does not seem dependent on since it can occur at nonpermissive temperature a top1-top2 ts mutant. Whether this change linking number is due an unusual form or whether new enzyme has yet determined. The results suggest normally required relax induced supercoils. A model discussed which considers role topoisomerases movement along template.