title: A novel c-Myc-responsive gene, JPO1, participates in neoplastic transformation.
abstract: We have identified a novel c-Myc-responsive gene, named JPO1, by representational difference analysis. JPO1 responds to two inducible c-Myc systems and behaves as a direct c-Myc target gene. JPO1 mRNA expression is readily detectable in the thymus, small intestine, and colon, whereas expression is relatively low in spleen, bone marrow, and peripheral leukocytes. We cloned a full-length JPO1 cDNA that encodes a 47-kDa nuclear protein. To determine the role of JPO1 in Myc-mediated cellular phenotypes, stable Rat1a fibroblasts overexpressing JPO1 were tested and compared with transformed Rat1a-Myc cells. Although JPO1 has a diminished transforming activity as compared with c-Myc, JPO1 complements a transformation-defective Myc Box II mutant in the Rat1a transformation assay. This complementation provides evidence for a genetic link between c-Myc and JPO1. Similar to c-Myc, JPO1 overexpression enhances the clonogenicity of CB33 human lymphoblastoid cells in methylcellulose assays. These observations suggest that JPO1 participates in c-Myc-mediated transformation, supporting an emerging concept that c-Myc target genes constitute nodal points in a network of pathways that lead from c-Myc to various Myc-related phenotypes and ultimately to tumorigenesis.
authors.affiliation: Program in Human Genetics and Molecular Biology, Department of Medicine, Johns Hopkins Oncology Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205,USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Prescott
authors.forename: R C
authors.initials: RC
authors.lastname: Osthus
authors.forename: L A
authors.initials: LA
authors.lastname: Lee
authors.forename: B C
authors.initials: BC
authors.lastname: Lewis
authors.forename: H
authors.initials: H
authors.lastname: Shim
authors.forename: J F
authors.initials: JF
authors.lastname: Barrett
authors.forename: Q
authors.initials: Q
authors.lastname: Guo
authors.forename: A L
authors.initials: AL
authors.lastname: Hawkins
authors.forename: C A
authors.initials: CA
authors.lastname: Griffin
authors.forename: C V
authors.initials: CV
authors.lastname: Dang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2; D003001:Cloning, Molecular; D018076:DNA, Complementary; D016259:Genes, myc; D005816:Genetic Complementation Test; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D051381:Rats
chemical_list: C445325:CDCA7 protein, human; D018076:DNA, Complementary; D009687:Nuclear Proteins