Dataset Information

The UL97 gene product of human cytomegalovirus is an early-late protein with a nuclear localization but is not a nucleoside kinase.

ABSTRACT: The temporal expression of the UL97 gene product during human cytomegalovirus (HCMV) infection of human foreskin fibroblasts (HFF) and subcellular localization of this protein were analyzed by using a polyclonal antiserum raised against a truncated UL97 protein of 47 kDa. The UL97 protein was detectable 16 h after infection by Western blot (immunoblot) analysis. Since only reduced UL97 expression occurred in the presence of two inhibitors of DNA replication, phosphonoacetic acid and ganciclovir, we conclude that UL97 is an early-late gene, requiring DNA replication for maximum expression. By indirect immunofluorescence, the protein could be visualized in the nuclei of virus-infected HFF 22 h after infection. Nuclear localization of the UL97 protein was also detected in thymidine kinase-deficient 143B cells infected with a recombinant vaccinia virus containing the entire UL97 open reading frame (ORF), as well as in HFF transiently expressing the entire UL97 ORF under the control of HCMV major immediate-early promoter. However, transiently expressed 5'-terminal deletion mutants of the UL97 ORF in addition showed a cytoplasmic localization of the UL97 protein, confirming the presence of a nuclear localization site in the N-terminal region of the protein. Our high-pressure liquid chromatography analyses confirmed the ganciclovir phosphorylation by the UL97 protein, but no specific phosphorylation of natural nucleosides was observed, indicating that the UL97 protein is not a nucleoside kinase. During plaque purification of recombinant UL97-deficient HCMV, this virus was growth defective; hence, we presume that UL97 may be essential for the viral life cycle.

SUBMITTER: Michel D

PROVIDER: S-EPMC190660 | biostudies-other | 1996 Sep

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

The UL97 gene product of human cytomegalovirus is an early-late protein with a nuclear localization but is not a nucleoside kinase.

Michel D D Pavić I I Zimmermann A A Haupt E E Wunderlich K K Heuschmid M M Mertens T T

Journal of virology 19960901 9

The temporal expression of the UL97 gene product during human cytomegalovirus (HCMV) infection of human foreskin fibroblasts (HFF) and subcellular localization of this protein were analyzed by using a polyclonal antiserum raised against a truncated UL97 protein of 47 kDa. The UL97 protein was detectable 16 h after infection by Western blot (immunoblot) analysis. Since only reduced UL97 expression occurred in the presence of two inhibitors of DNA replication, phosphonoacetic acid and ganciclovir, ...[more]

PMID: 8709262

Similar Datasets

Project description:The DNA sequence and transcription pattern of human cytomegalovirus early gene UL84 were analyzed. This gene was mapped within a 2.6-kb PstI fragment located between 0.534 and 0.545 map unit of the large unique segment of the human cytomegalovirus genome, which is adjacent to the pp65 and pp71 genes. A 2.0-kb mRNA was transcribed from this region in the same leftward direction as the mRNAs of the pp65 and pp71 genes. The message was first detected at 2.5 h postinfection and reached a maximal level between 72 and 96 h postinfection. The nucleotide sequences of the 2.6-kb PstI genomic DNA fragment and the cDNA derived from this region were determined. The resulting data revealed a polyadenylation signal (AATAAA) located 14 nucleotides upstream from the poly(A) tail of the cDNA and a 1,761-bp open reading frame capable of encoding a 65-kDa polypeptide. A potential leucine zipper was found in the N-terminal half of the peptide molecule between amino acids 114 and 135. In addition, a different periodic leucine repeat with leucine at every eighth position was found between amino acids 325 and 373. The transcriptional initiation site of this early gene was determined by primer extension analysis. A putative TATA box (TATTTAA) located 24 bp upstream of the cap site and several inverted repeats were found in the region further upstream of the TATA box. To test whether the open reading frame of this cDNA encodes a virus-specific protein, the cDNA was overexpressed in Escherichia coli as a fusion protein used to generate antibodies in rabbits. A protein with a molecular size of 65 kDa was detected in the infected-cell extracts harvested at 6 to 72 h postinfection, but not in purified virions, using immunoblot analysis. Both nuclear and cytoplasmic fluorescences were found at late stages of virus infection. From the results obtained, we postulate that UL84 may be a stable, virus-specific, nonstructural protein capable of forming a homo- or heterodimeric molecule.

Project description:The CMVpp65 protein contains 2 bipartite nuclear localization signals (NLS) at 415-438aa and 537-561aa near the carboxy terminus of CMVpp65 and a phosphate binding site related to kinase activity at lysine-436. A mutation of pp65 having K436N (CMVpp65mII) and further deletion of aa537-561 resulted in a novel protein (pp65mIINLSKO) that is kinase-less and has markedly reduced nuclear localization. The purpose of this report was to study the biologic characterization of this protein and its immunogenicity compared to native pp65.Using RNA microarray analysis, expression of the CMVpp65mIINLSKO had less effect on cell cycle pathways than did the native CMVpp65 and a greater effect on cell surface signalling pathways involving immune activity. It is concluded that the removal of the primary NLS motif from pp65 does not impair its immunogenicity and may actually be advantageous in the design of a vaccine. Keywords: comparison of cellular response to wild-type gene expression vs a mutated gene. The MRC-5 cells were transduced in triplicate, with rAAVintA, rAAVpp65N, rAAVpp65NLSKO for 48hrs and the total RNA was purified with RNeasy kit (Qiagen, Valencia, CA) according to the manufacturer’s instructions. One µg of each sample was processed using the Affymetrix GeneChip Whole Transcript Sense Target Labeling Assay. After ribosomal RNA reduction (Invitrogen, Carlsbad, CA) to remove most of the 18S and 28S rRNAs, the GeneChip WT (whole transcript) cDNA Synthesis Kit, WT cDNA Amplification Kit, and WT Terminal Labeling Kit (Affymetrix, Inc., Santa Clara, CA) were used for target preparation. Ten µg of cRNA (antisense RNA) were added to the second-cycle cDNA reaction followed by fragmentation and Terminal Labeling process. The hybridization cocktails containing 2.5 ug of the fragmented, end-labeled cDNA were applied to the GeneChip® Human Gene 1.0 ST arrays. The Genechip® Human Gene 1.0 ST array was chosen because it offers the whole transcript coverage consisting of 28,869 genes on the array by approximately 26 probes spread across the full length of the gene.

Project description:Human cytomegalovirus (HCMV) is a prototypic betaherpesvirus which causes severe manifestations in individuals with impaired or immature immunity. To investigate cytomegalovirus-induced pathogenesis and virus-specific immune responses, mouse cytomegalovirus (MCMV) infections in mice are employed as accepted small animal model. MCMV and HCMV share co-linear genomes and encode several homologous proteins. Due to the size and complexity of CMV genomes, the molecular functions of numerous cytomegaloviral gene products remain to be elucidated. While the essential nature of viral genes highlights their biological relevance, it renders functional studies particularly cumbersome by precluding experiments in the infection context. The HCMV-encoded protein pUL34 binds the HCMV genome and regulates viral gene expression (e.g., of US3). Several groups provided compelling evidence that UL34 is essential for HCMV replication. MCMV encodes the homologous protein pM34 (34% identical and 55% similar). Based on unsuccessful attempts to reconstitute M34-deficient virus from a bacterial artificial chromosome (BAC), M34 was previously classified as essential for MCMV replication. To characterize pM34 during viral infection, we engineered and analyzed an MCMV mutant expressing an HA-epitope-tagged pM34 which was expressed with early-late kinetics and localized in the nucleus. Additionally, we generated an M34-deficient ("ΔM34") MCMV-BAC by replacing the entire M34 coding sequence by a kanamycin resistance cassette. The deletion of M34 was confirmed by Southern blot and PCR. Unexpectedly, we could reconstitute replicating ΔM34-MCMV upon transfection of the BAC DNA into mouse embryonic fibroblasts. The absence of M34 from the genome of the replicating ΔM34-MCMV was also confirmed. Accordingly, a ΔM34-MCMV, in which the kanamycin cassette was excised by frt/Flp-mediated recombination, was also replication competent. In order to corroborate the absence of pM34 protein, the M34 deletion was recapitulated on the background of M34HA, which yielded replicating virus devoid of detectable pM34HA protein. The replication of MCMVs lacking M34 was found to be 10- to 100-fold reduced as compared to wt-MCMV which might explain previous unsuccessful reconstitution attempts conducted by others. Taken together, our findings reveal that MCMV remains replication competent despite the absence of M34, enabling functional studies in the infection context.

Dataset Information

The UL97 gene product of human cytomegalovirus is an early-late protein with a nuclear localization but is not a nucleoside kinase.

Publications

The UL97 gene product of human cytomegalovirus is an early-late protein with a nuclear localization but is not a nucleoside kinase.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets