title: Human DNA topoisomerase I is encoded by a single-copy gene that maps to chromosome region 20q12-13.2.
abstract: cDNA clones of the human TOP1 gene encoding DNA topoisomerase I (EC 5.99.1.2) have been obtained by immunochemical screening of phage lambda libraries expressing human cDNA segments, using rabbit antibodies raised against purified HeLa DNA topoisomerase I. Hybridization patterns between the cloned cDNA sequences and human cellular DNA and cytoplasmic mRNAs indicate that human TOP1 is a single-copy gene. The chromosomal location of the gene has been mapped to the long arm of chromosome 20, in the region q12-13.2, by hybridization of a radioactively labeled TOP1 cDNA probe to human metaphase chromosomes and to a panel of rodent-human somatic hybrids retaining overlapping subsets of human chromosomes.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China.
authors.forename: C C
authors.initials: CC
authors.lastname: Juan
authors.forename: J L
authors.initials: JL
authors.lastname: Hwang
authors.forename: A A
authors.initials: AA
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Whang-Peng
authors.forename: T
authors.initials: T
authors.lastname: Knutsen
authors.forename: K
authors.initials: K
authors.lastname: Huebner
authors.forename: C M
authors.initials: CM
authors.lastname: Croce
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: J C
authors.initials: JC
authors.lastname: Wang
authors.forename: L F
authors.initials: LF
authors.lastname: Liu
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D002890:Chromosomes, Human, Pair 20; D004264:DNA Topoisomerases, Type I / Q000235:genetics*; D005796:Genes; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D006822:Hybrid Cells / Q000201:enzymology; D007621:Karyotyping; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D004264:DNA Topoisomerases, Type I