The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
Gene Review

topB  -  DNA topoisomerase III

Escherichia coli str. K-12 substr. MG1655

Synonyms: ECK1761, JW1752, mutR
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of topB


High impact information on topB


Biological context of topB

  • The products of the orf183 and topB genes were required neither for selenoprotein biosynthesis nor for selenation of tRNAs. selAB transcription was driven by a single, weak promoter; however, two major selD operon transcripts were identified [7].
  • Frameshift mutations in topB strain also significantly increased compared with those of wild-type (17 vs. 2%) [8].
  • The present data suggest that topB is a novel class of mutator that strongly induces repeated sequence dependent deletion mutagenesis and high frequencies of frameshift mutagenesis [8].
  • A 17-amino-acid residue domain has been identified in Escherichia coli DNA topoisomerase III (Topo III) that is essential for Topo III-mediated resolution of DNA replication intermediates in vitro [9].

Associations of topB with chemical compounds

  • (ii) Mutations in mutR can be induced with the frameshift mutagen ICR-191 [10].

Other interactions of topB


  1. Molecular cloning and DNA sequence analysis of Escherichia coli topB, the gene encoding topoisomerase III. DiGate, R.J., Marians, K.J. J. Biol. Chem. (1989) [Pubmed]
  2. Crystal structure of a complex of a type IA DNA topoisomerase with a single-stranded DNA molecule. Changela, A., DiGate, R.J., Mondragón, A. Nature (2001) [Pubmed]
  3. Type I topoisomerase activity is required for proper chromosomal segregation in Escherichia coli. Zhu, Q., Pongpech, P., DiGate, R.J. Proc. Natl. Acad. Sci. U.S.A. (2001) [Pubmed]
  4. The traE gene of plasmid RP4 encodes a homologue of Escherichia coli DNA topoisomerase III. Li, Z., Hiasa, H., Kumar, U., DiGate, R.J. J. Biol. Chem. (1997) [Pubmed]
  5. Escherichia coli DNA topoisomerase III is a site-specific DNA binding protein that binds asymmetrically to its cleavage site. Zhang, H.L., Malpure, S., DiGate, R.J. J. Biol. Chem. (1995) [Pubmed]
  6. Characterization of Exc, a novel protein required for the excision of Bacteroides conjugative transposon. Sutanto, Y., Shoemaker, N.B., Gardner, J.F., Salyers, A.A. Mol. Microbiol. (2002) [Pubmed]
  7. Expression and operon structure of the sel genes of Escherichia coli and identification of a third selenium-containing formate dehydrogenase isoenzyme. Sawers, G., Heider, J., Zehelein, E., Böck, A. J. Bacteriol. (1991) [Pubmed]
  8. An Escherichia coli topB mutant increases deletion and frameshift mutations in the supF target gene. Uematsu, N., Eda, S., Yamamoto, K. Mutat. Res. (1997) [Pubmed]
  9. Identification of a unique domain essential for Escherichia coli DNA topoisomerase III-catalysed decatenation of replication intermediates. Li, Z., Mondragón, A., Hiasa, H., Marians, K.J., DiGate, R.J. Mol. Microbiol. (2000) [Pubmed]
  10. Further characterization of a non-essential mutator gene in Escherichia coli K-12. Hoess, R.H., Fan, D.P. J. Bacteriol. (1975) [Pubmed]
  11. Isolation of the topB gene encoding DNA topoisomerase III as a multicopy suppressor of topA null mutations in Escherichia coli. Broccoli, S., Phoenix, P., Drolet, M. Mol. Microbiol. (2000) [Pubmed]
WikiGenes - Universities