Dataset Information

The human cytomegalovirus UL76 gene regulates the level of expression of the UL77 gene.

ABSTRACT:

Background

Human cytomegalovirus (HCMV) can be reactivated under immunosuppressive conditions causing several fatal pneumonitis, hepatitis, retinitis, and gastrointestinal diseases. HCMV also causes deafness and mental retardation in neonates when primary infection has occurred during pregnancy. In the genome of HCMV at least 194 known open reading frames (ORFs) have been predicted, and approximately one-quarter, or 41 ORFs, are required for viral replication in cell culture. In contrast, the majority of the predicted ORFs are nonessential for viral replication in cell culture. However, it is also possible that these ORFs are required for the efficient viral replication in the host. The UL77 gene of HCMV is essential for viral replication and has a role in viral DNA packaging. The function of the upstream UL76 gene in the HCMV-infected cells is not understood. UL76 and UL77 are cistons on the same viral mRNA and a conventional 5' mRNA for UL77 has not been detected. The vast majority of eukaryotic mRNAs are monocistronic, i.e., they encode only a single protein.

Methodology/principal findings

To determine whether the UL76 ORF affects UL77 gene expression, we mutated UL76 by ORF frame-shifts, stop codons or deletion of the viral gene. The effect on UL77 protein expression was determined by either transfection of expression plasmids or infection with recombinant viruses. Mutation of UL76 ORF significantly increased the level of UL77 protein expression. However, deletion of UL76 upstream of the UL77 ORF had only marginal effects on viral growth.

Conclusions/significance

While UL76 is not essential for viral replication, the UL76 ORF is involved in regulation of the level of UL77 protein expression in a manner dependent on the translation re-initiation. UL76 may fine-tune the UL77 expression for the efficient viral replication in the HCMV- infected cells.

SUBMITTER: Isomura H

PROVIDER: S-EPMC2912765 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature

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Publications

The human cytomegalovirus UL76 gene regulates the level of expression of the UL77 gene.

Isomura Hiroki H Stinski Mark F MF Murata Takayuki T Nakayama Sanae S Chiba Shigeki S Akatsuka Yoshiki Y Kanda Teru T Tsurumi Tatsuya T

PloS one 20100730 7

<h4>Background</h4>Human cytomegalovirus (HCMV) can be reactivated under immunosuppressive conditions causing several fatal pneumonitis, hepatitis, retinitis, and gastrointestinal diseases. HCMV also causes deafness and mental retardation in neonates when primary infection has occurred during pregnancy. In the genome of HCMV at least 194 known open reading frames (ORFs) have been predicted, and approximately one-quarter, or 41 ORFs, are required for viral replication in cell culture. In contrast ...[more]

PMID: 20689582

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Project description:Human cytomegalovirus (HCMV) is a common cause of morbidity and mortality in immunocompromised and immunosuppressed individuals. During infection, HCMV is known to employ host transcription factors to facilitate viral gene expression. To further understand the previously observed delayed viral replication and protein expression in p53 knockout cells, we conducted microarray analyses on p53+/+ and p53-/- immortalized fibroblast cell lines. At 12 hpi, applying the significance criteria defined above, no genes showed a significant difference in any of the comparisons. At 24 hpi, we found 19 genes to be significantly different in the THF versus p53-/- comparison and 14 genes to be significantly different in the HFF versus p53-/- comparison. Eleven genes were shared between HFF and THF cells when compared to p53-/- cells (UL30, UL54, UL63, UL65, UL69, UL75, UL110, UL122, IRL4, IRS1, TRS1, shown in bold in Table 1). Eight genes were unique in the THF versus p53-/- comparison (UL48, UL68, UL84, UL100, UL106, UL109, UL111, RL5A), and three genes in the HFF versus p53-/- cell comparison (UL14, UL16, US2). When comparing HFF and THF cells, only US2 showed a significant difference. The ratio (HFF versus p53-/- divided by THF versus p53-/-) of the expression levels of the eleven shared genes from the HFF versus p53-/- and THF versus p53-/- comparisons was an averaged 1.2, indicating that, with the exception of US2, these two cell lines behaved similarly with respect to p53-driven viral gene expression. Keywords: time course, virus, cytomegalo, hhv5, infection, p53 Each slide consisted of 4 arrays. Each array consisted of 305 control features, 1265 cellular gene features and 670 viral gene features. The study was performed on 6 slides (HFF-THF, HFF-p53-/-, THF-p53-/- at 12 and 24 hpi). 3 arrays per slide were hybridized with 3 biological replicates of labelled RNA, the 4th array was hybridized with an equimolar mixture of the 3 biological replicate samples. This array was used for control purposes only, and the results were not used for downstream calculations. Each slide was stripped and reprobed two times to provide 3 technical replicates of each sample. As our experiments concentrated on viral genes and their expression, cellular genes were not further analyzed in this study.

Dataset Information

The human cytomegalovirus UL76 gene regulates the level of expression of the UL77 gene.

Background

Methodology/principal findings

Conclusions/significance

Publications

The human cytomegalovirus UL76 gene regulates the level of expression of the UL77 gene.

Similar Datasets

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