title: cDNA cloning of Physarum polycephalum DNA topoisomerase I and expression analysis in plasmodia treated with cAMP.
abstract: cDNA encoding DNA topoisomerase I from Physarum polycephalum was isolated from a poly(A)+ -primed library (3'-region) and by PCR (5'-region). The coding region of cDNA was 3045 bp, encoding a polypeptide of molecular mass of 112 kDa. Identity between predicted amino acids sequences of conserved domains and corresponding domains from another eukaryotic type I DNA topoisomerases varied from 33.2 to 53.5% for the core domain and from 33.8 to 57.4% for the C-terminal domain. A peculiar feature of Physarum DNA topoisomerase I was a stretch of repeated KPAX...X motifs in the N-terminal domain of the polypeptide. Although treatment of the plasmodia with db-cAMP increased relaxing activity of the DNA topoisomerase I several-fold, there was only a slight increase in the mRNA level.
authors.affiliation: Institute of Biochemistry, Warsaw University, Warsaw, Poland.
authors.forename: R
authors.initials: R
authors.lastname: Czerwínski
authors.forename: A
authors.initials: A
authors.lastname: Lipniacki
authors.forename: K
authors.initials: K
authors.lastname: Staroń
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003994:Bucladesine / Q000494:pharmacology*; D019976:Cloning, Organism; D017124:Conserved Sequence; D000242:Cyclic AMP / Q000378:metabolism; D004264:DNA Topoisomerases, Type I / Q000096:biosynthesis* / Q000737:chemistry; D018076:DNA, Complementary; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016839:Physarum polycephalum / Q000201:enzymology* / Q000235:genetics; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013768:Tetrahymena / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D003994:Bucladesine; D000242:Cyclic AMP; D004264:DNA Topoisomerases, Type I