Characterization of the human herpesvirus 6A U23 gene

Hayashi, Mayuko; Yoshida, Kento; Tang, Huiping; Sadaoka, Tomohiko; Kawabata, Akiko; Jasirwan, Chyntia Olivia Maurine; Mori, Yasuko

doi:10.1016/j.virol.2013.12.004

Cited by 8 publications

(13 citation statements)

References 32 publications

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“…Only a handful of genes unique to roseoloviruses have been studied functionally. These include transactivators encoded by DR6 and U3, the U94 parvovirus rep gene homolog, immunoevasins encoded by U21, a non-essential Golgi-localizing non-structural glycoprotein encoded by U23 [17], and the gQ1 and gQ2 glycoproteins.…”

Section: Roseolovirus Genomes and Genesmentioning

confidence: 99%

Roseolovirus molecular biology: recent advances

Krug

Pellett

2014

Current Opinion in Virology

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Human herpesviruses 6A, −6B, and −7 (HHV-6A, −6B, and −7) are classified within the roseolovirus genus of the betaherpesvrus subfamily. Most humans likely harbor at least two of these large DNA viruses, and 1% of humans harbor germline chromosomally integrated HHV-6A or HHV-6B genomes. Differences at the genetic level manifest as distinct biologic properties during infection and disease. We provide a brief synopsis of roseolovirus replication and highlight the unique properties of their lifecycle and what is known about the viral gene products that mediate these functions. In the nearly 30 years since their discovery, we have only begun to unlock the molecular strategies these highly evolved pathogens employ to establish and maintain chronic infections in humans.

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Section: Roseolovirus Genomes and Genesmentioning

confidence: 99%

Roseolovirus molecular biology: recent advances

Krug

Pellett

2014

Current Opinion in Virology

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“…Construction of HHV-6A BACgB(N347K), HHV-6A BACgB(N347A), and their revertants. HHV-6A BACgB(N347K), HHV-6A BACgB(N347A), and their revertants were constructed by using two-step Redmediated mutagenesis as described previously (23,24,48,52).…”

Section: Methodsmentioning

confidence: 99%

The Neutralizing Linear Epitope of Human Herpesvirus 6A Glycoprotein B Does Not Affect Virus Infectivity

Wakata

Kanemoto

Tang

et al. 2018

J Virol

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Human herpesvirus 6A (HHV-6A) glycoprotein B (gB) is a glycoprotein consisting of 830 amino acids and is essential for the growth of the virus. Previously, we reported that a neutralizing monoclonal antibody (MAb) called 87-y-13 specifically reacts with HHV-6A gB, and we identified its epitope residue at asparagine (Asn) 347 on gB. In this study, we examined whether the epitope recognized by the neutralizing MAb is essential for HHV-6A infection. We constructed HHV-6A bacterial artificial chromosome (BAC) genomes harboring substitutions at Asn347, namely, HHV-6A BACgB(N347K) and HHV-6A BACgB(N347A). These mutant viruses could be reconstituted and propagated in the same manner as the wild type and their revertants, and MAb 87-y-13 could not inhibit infection by either mutant. In a cell-cell fusion assay, Asn at position 347 on gB was found to be nonessential for cell-cell fusion. In addition, in building an HHV-6A gB homology model, we found that the epitope of the neutralizing MAb is located on domain II of gB and is accessible to solvents. These results indicate that Asn at position 347, the linear epitope of the neutralizing MAb, does not affect HHV-6A infectivity. Glycoprotein B (gB) is one of the most conserved glycoproteins among all herpesviruses and is a key factor for virus entry. Therefore, antibodies targeted to gB may neutralize virus entry. Human herpesvirus 6A (HHV-6A) encodes gB, which is translated to a protein of about 830 amino acids (aa). Using a monoclonal antibody (MAb) for HHV-6A gB, which has a neutralizing linear epitope, we analyzed the role of its epitope residue, N347, in HHV-6A infectivity. Interestingly, this gB linear epitope residue, N347, was not essential for HHV-6A growth. By constructing a homology model of HHV-6A gB, we found that N347 was located in the region corresponding to domain II. Therefore, with regard to its neutralizing activity against HHV-6A infection, the epitope on gB might be exposed to solvents, suggesting that it might be a target of the immune system.

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“…Monoclonal antibodies anti-U27 Mab, U11 Mab, and gQ1 Mab (gQ1 119) have been described previously. [35][36][37] Antiα-tubulin was purchased from Sigma-Aldrich (St. Louis, MO, USA), and HRP-linked sheep antimouse IgG secondary antibody was purchased from GE Healthcare Biosciences (Uppsala, Sweden).…”

Section: Antibodiesmentioning

confidence: 99%

“…To construct the HHV-6ABACU27 mutant (HHV-6ABACU27mut) DNA, we used a two-step Red-mediated recombination system in Escherichia coli GS1783. 33,36,37,[39][40][41] The HHV-6ABACU27mut was designed with a frameshift mutation comprising an additional "G" nucleotide after the position of lysine 33 in the U27 gene ( Figure 1b). The primers U1102 BAC U27 33893 I-Sce1 F (5′-gaaacgagagaac cgccgaccctagcttttcatatgaaaaGgctggaaaactattaataaaAGGATG ACGACGATAAGTAGGG-3′) and U1102 BAC U27 33893 aphAI R (5′-ttttgcaaacgctttaagcgatttattaatagttttccagcCttttc atatgaaaagctaggCAACCAATTAACCAATTCTGATTAG-3′) were used to amplify the kanamycin-resistant gene from pEP-KanS 40 (hereafter, the lower case letters in primers indicate the nucleotide sequences identical to the U27 gene of the HHV-6A U1102 strain).…”

Section: Construction Of Hhv-6abacu27mut Dna and Its Revertantmentioning

confidence: 99%

“…[35][36][37] In brief, the samples were the cells collected after the virus reconstitution experiment as described above, or 293T cells transfected with the pCAGGS-AU27 plasmid and cultured for 1 day in the same manner as described previously. 36 The cells were collected and lysed by sonication, then incubated at 100°C for 10 min. The proteins were separated by SDS-PAGE, and transferred to a polyvinylidene difluoride membrane by wet transfer.…”

Section: Western Blottingmentioning

confidence: 99%

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Human herpesvirus 6A U27 plays an essential role for the virus propagation

Poetranto

Wakata

Tjan

et al. 2020

Microbiology and Immunology

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Human herpesvirus 6A (HHV-6A) is a member of the genus Roseolovirus and the subfamily Betaherpesvirinae. It is similar to and human cytomegalovirus (HCMV). HHV-6A encodes a 41 kDa nuclear phosphoprotein, U27, which acts as a processivity factor in the replication of the viral DNA. HHV-6A U27 has 43% amino acid sequence homology with HCMV UL44, which is important for DNA replication. A previous study on HHV-6A U27 revealed that it greatly increases the in vitro DNA synthesis activity of HHV-6A DNA polymerase. However, the role of U27 during the HHV-6A virus replication process remains unclear. In this study, we constructed a U27-deficient HHV-6A mutant (HHV-6ABACU27mut) with a frameshift insertion at the U27 gene using an HHV-6A bacterial artificial chromosome (BAC) system. Viral reconstitution from the mutant BAC DNA was not detected, in contrast to the wild type and the revertant from the U27 mutant. This suggests that U27 plays a critical role in the life cycle of HHV-6A.

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Characterization of the human herpesvirus 6A U23 gene

Cited by 8 publications

References 32 publications

Roseolovirus molecular biology: recent advances

Roseolovirus molecular biology: recent advances

The Neutralizing Linear Epitope of Human Herpesvirus 6A Glycoprotein B Does Not Affect Virus Infectivity

Human herpesvirus 6A U27 plays an essential role for the virus propagation

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