Research Article
- Efficiency of reverse genetics methods for rescuing severe acute respiratory syndrome coronavirus 2
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Chang-Joo Park, Taehun Kim, Seung-Min Yoo, Myung-Shin Lee, Nam-Hyuk Cho, Changhoon Park
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J. Microbiol. 2025;63(2):e2411023. Published online February 27, 2025
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DOI: https://doi.org/10.71150/jm.2411023
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Abstract
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- Bacteria-free reverse genetics techniques are crucial for the efficient generation of recombinant viruses, bypassing the need for labor-intensive bacterial cloning. These methods are particularly relevant for studying the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19. This study compared the efficiency of three bacteria-free approaches—circular polymerase extension reaction (CPER) with and without nick sealing and infectious sub-genomic amplicons (ISA)—to bacterial artificial chromosome (BAC)-based technology for rescuing SARS-CoV-2. Significant differences in viral titers following transfection were observed between methods. CPER with nick sealing generated virus titers comparable to those of the BAC-based method and 10 times higher than those of the standard CPER. In contrast, ISA demonstrated extremely low efficiency, as cytopathic effects were detected only after two passages. All rescued viruses exhibited replication kinetics consistent with those of the original strain, with no significant deviation in replication capacity. Furthermore, the utility of CPER and ISA in genetically modifying SARS-CoV-2 was demonstrated by successfully inserting the gene encoding green fluorescent protein into the genome. Overall, this study underscores the potential of bacteria-free methods, such as CPER and ISA, in advancing SARS-CoV-2 research while highlighting their significant differences in efficiency.
Review
- Protective and pathogenic role of humoral responses in COVID-19
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Uni Park , Nam-Hyuk Cho
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J. Microbiol. 2022;60(3):268-275. Published online March 2, 2022
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DOI: https://doi.org/10.1007/s12275-022-2037-8
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Abstract
- Since the advent of SARS-CoV-2 in Dec. 2019, the global endeavor
to identify the pathogenic mechanism of COVID-19
has been ongoing. Although humoral immunity including
neutralizing activity play an important role in protection from
the viral pathogen, dysregulated antibody responses may be
associated with the pathogenic progression of COVID-19,
especially in high-risk individuals. In addition, SARS-CoV-2
spike-specific antibodies acquired by prior infection or vaccination
act as immune pressure, driving continuous population
turnover by selecting for antibody-escaping mutations.
Here, we review accumulating knowledge on the potential
role of humoral immune responses in COVID-19, primarily
focusing on their beneficial and pathogenic properties. Understanding
the multifaceted regulatory mechanisms of humoral
responses during SARS-CoV-2 infection can help us to develop
more effective therapeutics, as well as protective measures
against the ongoing pandemic.
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Citations
Citations to this article as recorded by

- Rise in broadly cross-reactive adaptive immunity against human β-coronaviruses in MERS-recovered patients during the COVID-19 pandemic
So-Hee Kim, Yuri Kim, Sangeun Jeon, Uni Park, Ju-Il Kang, Kyeongseok Jeon, Hye-Ran Kim, Songhyeok Oh, Ji-Young Rhee, Jae-Phil Choi, Wan Beom Park, Sang Won Park, Jeong-Sun Yang, Joo-Yeon Lee, Jihye Kang, Hyoung-Shik Shin, Yeonjae Kim, Seungtaek Kim, Yeon-
Science Advances.2024;[Epub] CrossRef - Distinctive Combinations of RBD Mutations Contribute to Antibody Evasion in the Case of the SARS-CoV-2 Beta Variant
Tae-Hun Kim, Sojung Bae, Sunggeun Goo, Jinjong Myoung
Journal of Microbiology and Biotechnology.2023; 33(12): 1587. CrossRef - Two years of COVID-19 pandemic: where are we now?
Jinjong Myoung
Journal of Microbiology.2022; 60(3): 235. CrossRef
Research Support, Non-U.S. Gov't
- Inhibition of eukaryotic translation by tetratricopeptide-repeat proteins of Orientia tsutsugamushi
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Sunyoung Bang , Chan-Ki Min , Na-Young Ha , Myung-Sik Choi , Ik-Sang Kim , Yeon-Sook Kim , Nam-Hyuk Cho
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J. Microbiol. 2016;54(2):136-144. Published online February 2, 2016
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DOI: https://doi.org/10.1007/s12275-016-5599-5
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Abstract
- Orientia tsutsugamushi, an obligate intracellular bacterium, is
the causative agent of scrub typhus. The genome of Orientia
tsutsugamushi has revealed multiple ORFs encoding tetratricopeptide-
repeat (TPR) proteins. The TPR protein family
has been shown to be involved in a diverse spectrum of cellular
functions such as cell cycle control, transcription, protein
transport, and protein folding, especially in eukaryotic
cells. However, little is known about the function of the TPR
proteins in O. tsutsugamushi. To investigate the potential role
of TPR proteins in host-pathogen interaction, two oriential
TPR proteins were expressed in E. coli and applied for GSTpull
down assay. DDX3, a DEAD-box containing RNA helicase,
was identified as a specific eukaryotic target of the TPR
proteins. Since the RNA helicase is involved in multiple RNAmodifying
processes such as initiation of translation reaction,
we performed in vitro translation assay in the presence
of GST-TPR fusion proteins by using rabbit reticulocyte lysate
system. The TPR proteins inhibited in vitro translation
of a reporter luciferase in a dose dependent manner whereas
the GST control proteins did not. These results suggested TPR
proteins of O. tsutsugamushi might be involved in the modulation
of eukarytotic translation through the interaction with
DDX3 RNA helicase after secretion into host cytoplasm.
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Citations
Citations to this article as recorded by

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Orientia tsutsugamushi:
comprehensive analysis of the mobilome of a highly fragmented and repetitive genome reveals the capacity for ongoing lateral gene transfer in an obligate intracellular bacterium
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Published Erratum