title: Negative and positive regulation by a short segment in the 5'-flanking region of the human cytomegalovirus major immediate-early gene.
abstract: To analyze the significance of inducible DNase I-hypersensitive sites occurring in the 5'-flanking sequence of the major immediate-early gene of human cytomegalovirus (HCMV), various deleted portions of the HCMV immediate-early promoter regulatory region were attached to the chloramphenicol acetyltransferase (CAT) gene and assayed for activity in transiently transfected undifferentiated and differentiated human teratocarcinoma cells, Tera-2. Assays of progressive deletions in the promoter regulatory region indicated that removal of a 395-base-pair portion of this element (nucleotides -750 to -1145) containing two inducible DNase I sites which correlate with gene expression resulted in a 7.5-fold increase in CAT activity in undifferentiated cells. However, in permissive differentiated Tera-2, human foreskin fibroblast, and HeLa cells, removal of this regulatory region resulted in decreased activity. In addition, attachment of this HCMV upstream element to a homologous or heterologous promoter increased activity three- to fivefold in permissive cells. Therefore, a cis regulatory element exists 5' to the enhancer of the major immediate-early gene of HCMV. This element negative modulates expression in nonpermissive cells but positively influences expression in permissive cells.
authors.affiliation: Department of Immunology, Research Institute of Scripps Clinic, La Jolla, California 92037.
authors.forename: J A
authors.initials: JA
authors.lastname: Nelson
authors.forename: C
authors.initials: C
authors.lastname: Reynolds-Kohler
authors.forename: B A
authors.initials: BA
authors.lastname: Smith
mesh_terms: D002460:Cell Line; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D003587:Cytomegalovirus / Q000235:genetics*; D004262:DNA Restriction Enzymes; D005809:Genes, Regulator; D005814:Genes, Viral; D006801:Humans
chemical_list: D004262:DNA Restriction Enzymes