title: The phosphoCTD-interacting domain of Topoisomerase I.
abstract: The N-terminal domain (NTD) of Drosophila melanogaster (Dm) Topoisomerase I has been shown to bind to RNA polymerase II, but the domain of RNAPII with which it interacts is not known. Using bacterially-expressed fusion proteins carrying all or half of the NTDs of Dm and human (Homo sapiens, Hs) Topo I, we demonstrate that the N-terminal half of each NTD binds directly to the hyperphosphorylated C-terminal repeat domain (phosphoCTD) of the largest RNAPII subunit, Rpb1. Thus, the amino terminal segment of metazoan Topo I (1-157 for Dm and 1-114 for Hs) contains a novel phosphoCTD-interacting domain that we designate the Topo I-Rpb1 interacting (TRI) domain. The long-known in vivo association of Topo I with active genes presumably can be attributed, wholly or in part, to the TRI domain-mediated binding of Topo I to the phosphoCTD of transcribing RNAPII.
authors.affiliation: Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Wu
authors.forename: Hemali P
authors.initials: HP
authors.lastname: Phatnani
authors.forename: Tao-Shih
authors.initials: TS
authors.lastname: Hsieh
authors.forename: Arno L
authors.initials: AL
authors.lastname: Greenleaf
mesh_terms: D000330:Aedes; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002645:Chickens; D004264:DNA Topoisomerases, Type I / Q000737:chemistry* / Q000235:genetics; D004331:Drosophila melanogaster; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D011993:Recombinant Fusion Proteins; D004264:DNA Topoisomerases, Type I