title: Isolation and characterization of a low-abundance splice variant from the human cytomegalovirus major immediate-early gene region.
abstract: The major immediate-early (IE) gene region of human cytomegalovirus (HCMV) encodes several proteins as a result of differential RNA splicing events. By expression vector cloning of HCMV IE mRNA, we isolated and characterized a cDNA for a novel splice variant from the major IE gene region. The RNA product is a derivative of the IE55 mRNA and contains an additional splice from nucleotides 170,635 to 170,307 in the IE2 gene region (UL122), resulting in a 1.4-kb mRNA. The predicted open reading frame codes for a 164-amino-acid protein with a calculated molecular mass of 18 kDa (IE18). Mung bean nuclease analysis and PCR were used to characterize expression of IE18 mRNA in HCMV-infected cells. While the 1.4-kb mRNA was detected in infected human fibroblasts in the presence of a protein synthesis inhibitor, it was not detectable during a normal infection. However, the 1.4-kb mRNA was readily detected in infected human monocyte-derived macrophages at IE times. These results suggest that the novel IE18 mRNA exhibits cell type-specific expression indicating differential regulation of the major IE gene region in different permissive cell types.
authors.affiliation: Department of Microbiology and Immunology, Eastern Virginia Medical School, Norfolk, 23501, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Kerry
authors.forename: A
authors.initials: A
authors.lastname: Sehgal
authors.forename: S W
authors.initials: SW
authors.lastname: Barlow
authors.forename: V J
authors.initials: VJ
authors.lastname: Cavanaugh
authors.forename: K
authors.initials: K
authors.lastname: Fish
authors.forename: J A
authors.initials: JA
authors.lastname: Nelson
authors.forename: R M
authors.initials: RM
authors.lastname: Stenberg
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D003587:Cytomegalovirus / Q000235:genetics*; D018076:DNA, Complementary; D017874:Immediate-Early Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D012326:RNA Splicing
chemical_list: D018076:DNA, Complementary; C093522:IE18 protein, Human cytomegalovirus; D017874:Immediate-Early Proteins