title: Isolation and Characterization of a Novel Human Radiosusceptibility Gene, NP95.
abstract: The murine nuclear protein Np95 has been shown to underlie resistance to ionizing radiation and other DNA insults or replication arrests in embryonic stem (ES) cells. Using the databases for expressed sequenced tags and a two-step PCR procedure, we isolated human NP95, the full-length human homologue of the murine Np95 cDNA, which consists of 4,327 bp with a single open reading frame (ORF) encoding a polypeptide of 793 amino acids and 73.3% homology to Np95. The ORF of human NP95 cDNA is identical to the UHRF1 (ubiquitin-like protein containing PHD and RING domain 1). The NP95 gene, assigned to 19p13.3, consists of 18 exons, spanning 60 kb. Several stable transformants from HEK293 and WI-38 cells that had been transfected with the antisense NP95 cDNA were, like the murine Np95-knockout ES cells, more sensitive to X rays, UV light and hydroxyurea than the corresponding parental cells. In HEK293 cells, the lack of NP95 did not affect the activities of topoisomerase IIalpha, whose expression had been demonstrated to be regulated by the inverted CCAAT box binding protein of 90 kDa (ICBP90) that closely resembles NP95 in amino acid sequence and in cDNA but differs greatly in genomic organization. These findings collectively indicate that the human NP95 gene is the functional orthologue of the murine Np95 gene.
authors.affiliation: Research Center for Radiation Safety, National Institute of Radiological Science, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Muto
authors.forename: Akira
authors.initials: A
authors.lastname: Fujimori
authors.forename: Mituru
authors.initials: M
authors.lastname: Nenoi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Daino
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Asato
authors.initials: A
authors.lastname: Kuroiwa
authors.forename: Eiko
authors.initials: E
authors.lastname: Kubo
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Kanari
authors.forename: Makoto
authors.initials: M
authors.lastname: Utsuno
authors.forename: Hideo
authors.initials: H
authors.lastname: Tsuji
authors.forename: Hideki
authors.initials: H
authors.lastname: Ukai
authors.forename: Kazuei
authors.initials: K
authors.lastname: Mita
authors.forename: Masahiko
authors.initials: M
authors.lastname: Takahagi
authors.forename: Kouichi
authors.initials: K
authors.lastname: Tatsumi
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007668:Kidney / Q000378:metabolism* / Q000528:radiation effects*; D051379:Mice; D008969:Molecular Sequence Data; D011829:Radiation Dosage; D011836:Radiation Tolerance / Q000502:physiology*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism*
chemical_list: C465619:UHRF2 protein, human; D044767:Ubiquitin-Protein Ligases