Human cytomegalovirus contains a phosphorylated matrix protein of 65,000 apparent molecular weight (65K phosphoprotein; pp65) and a related phosphoprotein of 71,0000 molecular weight (pp7l). The 65K phosphoprotein is usually by far the most abundant structural component found in culture-grown purified virus particles. This study describes the precise mapping of the genes for both polypeptides, giving the entire nucleotide sequences and the exact positions of the respective transcripts. The 65K phosphoprotein is coded for by the 5'-terminal part of an abundant 4-kilobase (kb) mRNA. The 71K phosphoprotein corresponds to the single translational reading frame of a rare nonspliced 1.9-kb mRNA that is coterminal with the 4-kb transcript. The promoter for 4-kb mRNA appears to be unusual in structure; it does not contain a characteristic TATA sequence. The expression of antigenic epitopes from pp65 may allow improved serodiagnosis of human cytomegalovirus infections.

Human cytomegalovirus contains a structural polypeptide that is 28 kilodaltons in apparent molecular size and is reactive in Western blot (immunoblot) analysis with the majority of human sera. The gene coding for this polypeptide was mapped on the genome of human cytomegalovirus strain AD169. A monoclonal antibody specific for the 28-kilodalton polypeptide was used to screen a cDNA library constructed from poly(A)+ RNA of human cytomegalovirus-infected cells in the procaryotic expression vector lambda gt11. Hybridization of cDNA with cosmid and plasmid clones mapped the gene to the HindIII R fragment. The gene was transcribed into a late 1.3-kilobase RNA. The nucleotide sequence of the coding region was determined. Parts of the 28-kilodalton polypeptide were expressed in Escherichia coli as hybrid proteins fused to beta-galactosidase. In Western blots these proteins were recognized by human sera. Antibodies raised against the hybrid proteins reacted specifically with the viral antigen in immunoprecipitations and Western blots. In vitro phosphorylation of HCMV virions and immunoprecipitation showed that the 28-kilodalton polypeptide was phosphorylated.

Objective: Disturbed expression of retinoic acid (RA) receptors (RAR/RXR) contributes to the pathogenesis and tumor progression of epithelial carcinomas. Design: To examine whether altered responses to retinoids may correlate with differences in RA receptor equipment, retinoid effects were examined in human thyroid carcinoma cell lines of various differentiation stages in culture and after xenotransplantation onto rodent models. Methods: Cell growth was assessed by the MTT test, mRNA expression was examined by Northern blot and quantitative competitive RT-PCR, and type I 5 0 -deiodinase (5 0 DI) activity was measured by in vitro deiodination assay. Nude rats and mice were used for xenotransplantation experiments. Results: All-trans-RA and RAR-selective synthetic retinoids stimulated activity and mRNA expression of the thyroid differentiation marker 5 0 DI in the follicular thyroid carcinoma cell line FTC-133. In the less differentiated FTC-238 cells, stimulation of 5 0 DI activity was less pronounced than in FTC-133 cells, and a reduced level of RARb mRNA was detected. In the anaplastic thyroid carcinoma cell lines HTh 74 and C 643, the activity of 5 0 DI was not increased by retinoids, and expression of RARa mRNA was reduced. Proliferation of FTC-133 and FTC-238 cells was decreased by all-trans-RA. Pretreatment of FTC-133 with RA resulted in a reduced tumor growth in xenotransplantation experiments as compared with untreated control cells. This reduction was less pronounced in the case of FTC-238 cells. Thus, retinoid therapy might be applied to treat follicular thyroid carcinomas. However, tumor-specific RAR repertoires need to be analyzed as a prerequisite for successful intervention with appropriate, probably receptor-selective retinoids.

No abstract

No abstract