Nucleotide sequence preference at rat liver and wheat germ type 1 DNA topoisomerase breakage sites in duplex SV40 DNA.

Journal Article (Journal Article)

The site specificities of the type 1 DNA topoisomerases (topo 1) from rat liver and wheat germ were investigated. The nucleotide sequence at break sites on duplex SV40 DNA were determined for 245 wheat germ topo 1 sites and 223 rat liver topo 1 sites over a region of 1781 nucleotides. The enzymes from the two different sources show similar, but not identical patterns of DNA strand breakage. The sites occur frequently, but are not broken with equal probabilities. Major sites of breakage occur on the average every one to two turns of the helix, thus if sites of breakage accurately represent topo 1 sites of activity, the DNA sequence alone would appear to place few limits on the access of the enzyme to DNA. Sequences around the strongest sites for both enzymes show a bias in base composition for the four nucleotides immediately 5' to the break site (-4 to -1 positions), but no bias is observed 3' to the site of breakage. Consensus sequences for both enzymes were determined. Variations from the consensus sequence appear to affect the two enzymes differently and may account for the differences observed in the specificity of breakage.

Full Text

Duke Authors

Cited Authors

  • Been, MD; Burgess, RR; Champoux, JJ

Published Date

  • April 11, 1984

Published In

Volume / Issue

  • 12 / 7

Start / End Page

  • 3097 - 3114

PubMed ID

  • 6326051

Pubmed Central ID

  • PMC318732

International Standard Serial Number (ISSN)

  • 0305-1048

Digital Object Identifier (DOI)

  • 10.1093/nar/12.7.3097


  • eng

Conference Location

  • England