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Qu R, Shan L, Sun Q, Wei Y, Deng P, Hou X. Quantification of 13C, 15N labelled compounds with 13C, 15N edited 1H Nuclear Magnetic Resonance spectroscopy. Talanta 2021; 224:121839. [PMID: 33379057 DOI: 10.1016/j.talanta.2020.121839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/15/2020] [Accepted: 10/28/2020] [Indexed: 10/23/2022]
Abstract
It was significant to detect isotope labelled compounds in biology and pharmacy. Based on a novel 1H Nuclear Magnetic Resonance (1H-NMR) technique, a simple, fast and green method has been successfully established to quantitatively detect 13C, 15N isotope labelled compounds. In this protocol, the couples between 1H and 13C, 15N nearby were removed, which greatly simplified the spectrum. At mean time, the multiple peaks led by 13C and 15N were combined into one peak, so the signal intensity was also significantly enhanced. Melamine was selected as the internal standard and five 13C, 15N isotope labelled compounds showed excellent linearity from 0.001 mM to 100 mM. A real polypeptide sample has quantitatively been detected.
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Affiliation(s)
- Runlian Qu
- Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Lu Shan
- Bruker (Beijing) Scientific Technology Co. Ltd., Beijing, 100192, China
| | - Qun Sun
- College of Life Sciences, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Yao Wei
- Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Pengchi Deng
- Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, 610064, China.
| | - Xiandeng Hou
- Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, 610064, China; College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
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Identification of the largest non-essential regions of the C-terminal portion in 3A protein of foot-and-mouth disease virus for replication in cell culture. Virol J 2020; 17:137. [PMID: 32928221 PMCID: PMC7489034 DOI: 10.1186/s12985-020-01379-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 07/02/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Recent study has shown that the C-terminal portion of 3A (amino acids (aa) 81-153) is not essential for foot-and-mouth disease virus replication in cell culture, however, the complete C-terminal portion (aa 77-153) of 3A is highly variable and prone to occur deletions and mutations, therefore, we presume that this region plays a very limited role and probablely is completely nonessential for virus viability. METHODS In this study, to identify the largest non-essential region of the C-terminal portion in 3A for FMDV viability, several deletions containing aa 80-153, 77-153 and 76-153 of 3A protein were introduced into an FMDV full-length infectious cDNA clone pOFS by the overlapping extension PCR. Additionally, to explore the importance of the highly conserved residue 76 L of 3A for the FMDV of Cathay topotype, two mutants containing 3A L76I and 3A L76V were generated based on the 3A deletion mutant by point mutation. We also introduced the enhanced green fluorescent protein (eGFP) into one of the 3A deletion mutants by the extension PCR to investigate the genetic flexibility of 3A to express foreign genes. All linearized full plasmids were transfected into BSR/T7 cells to rescue infectious foot-and-mouth disease viruses. The rescused viruses were analyzed by RT-PCR, nucleotide sequencing, immunofluorescence assay and western blot and were characterized by plaque assays and one-step growth kinetics. RESULTS The results demonstrated that the deletion of aa 80-153 and aa 77-153 and the substitutions of 3A L76I and 3A L76V did not affect the production of infectious virus, while the fusion of the eGFP gene to the C-terminus of 3A resulted in nonviable FMDV. CONCLUSIONS Our results firstly reported that the aa 77-153 rather than aa 81-153 of 3A protein was dispensable for FMDV replication in cell culture. This study is of great significance for development of FMD marker vaccine and foreign gene expression in the future.
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Modification of the second translation initiation site restricts the replication of foot-and-mouth disease virus in PK-15 cells. Appl Microbiol Biotechnol 2020; 104:8455-8466. [PMID: 32820373 PMCID: PMC7471169 DOI: 10.1007/s00253-020-10810-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/23/2020] [Accepted: 08/02/2020] [Indexed: 11/22/2022]
Abstract
Abstract The translation initiation of foot-and-mouth disease virus (FMDV) occurs at two alternative initiation sites (Lab AUG and Lb AUG). Usually, the Lb AUG is more favorably used to initiate protein synthesis than the Lab AUG. To explore the effect of Lb AUG on FMDV replication and obtain FMDV with restricted replication, this initiation codon was mutated to a variety of non-AUG codons (UGG, AUC, CUG, and AAA). Fortunately, the modifications did not prevent viral viability but influenced replication characteristics of some FMDV mutants in a cell-specific manner, as was shown by the similar replication in BHK-21 cells and delayed growth kinetics in PK-15 cells. This attenuated phenotype of FMDV mutants in PK-15 cells was found to be correlated with reduced abilities to cleave eIF4GI and suppress interference (IFN) expression. As leader (L) protein was reported to be responsible for eIF4GI cleavage and inhibition of IFN expression, the in vivo L protein synthesis was examined during the infection of FMDV mutants. Our results showed that not only the total yield of L proteins was severely influenced but also the individual yield of L protein was seen to be affected, which implied that both the relative usage of the two initiation sites and overall translation efficiency were changed by Lb AUG modifications. In addition, the in vitro translation activity was also negatively regulated by Lb AUG mutations. Collectively, these findings suggested that the restricted replications of Lb AUG-modified FMDVs were related to the delayed eIF4GI cleavage and decreased ability to block IFN expression but were mainly determined by the inefficient translation initiation. FMDVs precisely with modifications of Lb AUG initiation codon may represent safer seed viruses for vaccine production. Key points • The polyprotein translation of FMDV initiates at two alternative initiation sites (Lab AUG and Lb AUG). In order to explore the effect of Lb AUG on FMDV replication and obtain FMDV with restricted replication, the Lb initiation AUG was mutated to a variety of non-AUG codons (UGG, AUC, CUG, and AAA), and four FMDV mutants with Lb AUG modification were generated. • We found that partial FMDV mutants grew almost as well as WT virus in BHK-21 cells, a typical cell line used for FMD vaccine production, but displayed impaired replication in IFN-competent PK-15 cells. • The attenuation of mutant FMDVs in PK-15 cells was found to be correlated with delayed eIF4GI cleavage and decreased ability to block IFN expression. • We proved that the attenuated phenotype of Lb AUG-modified FMDVs was mainly determined by the inefficient translation initiation, as demonstrated by the decrease of total yield of L proteins and individual production of L protein. • We successfully generated genetically engineered FMDV with attenuated phenotype. The approach of precise engineering of FMDV with the modification of initiation codon provides a safe platform to produce inactivated antigen vaccines.
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Evaluation of immune responses of stabilised SAT2 antigens of foot-and-mouth disease in cattle. Vaccine 2017; 35:5426-5433. [DOI: 10.1016/j.vaccine.2017.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/01/2016] [Accepted: 02/01/2017] [Indexed: 11/20/2022]
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Liu Y, Zhu Z, Zhang M, Zheng H. Multifunctional roles of leader protein of foot-and-mouth disease viruses in suppressing host antiviral responses. Vet Res 2015; 46:127. [PMID: 26511922 PMCID: PMC4625562 DOI: 10.1186/s13567-015-0273-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/07/2015] [Indexed: 12/17/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) leader protein (Lpro) is a papain-like proteinase, which plays an important role in FMDV pathogenesis. Lpro exists as two forms, Lab and Lb, due to translation being initiated from two different start codons separated by 84 nucleotides. Lpro self-cleaves from the nascent viral polyprotein precursor as the first mature viral protein. In addition to its role as a viral proteinase, Lpro also has the ability to antagonize host antiviral effects. To promote FMDV replication, Lpro can suppress host antiviral responses by three different mechanisms: (1) cleavage of eukaryotic translation initiation factor 4 γ (eIF4G) to shut off host protein synthesis; (2) inhibition of host innate immune responses through restriction of interferon-α/β production; and (3) Lpro can also act as a deubiquitinase and catalyze deubiquitination of innate immune signaling molecules. In the light of recent functional and biochemical findings regarding Lpro, this review introduces the basic properties of Lpro and the mechanisms by which it antagonizes host antiviral responses.
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Affiliation(s)
- Yingqi Liu
- State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot and Mouth Diseases Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China. .,College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China.
| | - Zixiang Zhu
- State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot and Mouth Diseases Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
| | - Miaotao Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China.
| | - Haixue Zheng
- State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot and Mouth Diseases Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
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Jiang S, Bai X, Li P, Zhang M, Bao H, Sun P, Lu Z, Cao Y, Chen Y, Li D, Fu Y, Liu Z. Influence of Foot-and-Mouth Disease Virus O/CHN/Mya98/33-P Strain Leader Protein on Viral Replication and Host Innate Immunity. Viral Immunol 2015; 28:360-6. [PMID: 26186028 DOI: 10.1089/vim.2014.0150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) O/CHN/Mya98/33-P strain was isolated from the esophageal-pharyngeal fluid sample of cattle, and was shown to cause persistent infection. Its leader protein contains 200 amino acids with one amino acid deletion, which is upstream and next to the second initiation codon compared with the majority of FMDV Mya98 strains. The FMDV genome includes two initiation codons that can produce two different leader proteins, Lab (from the first AUG) and Lb (from the second AUG). For convenience, the inter-AUG region was named as La. Previously, it was found that a recombinant virus with Lab of FMDV O/CHN/Mya98/33-P strain had higher proliferation efficiency, and better ability to inhibit the host innate immune response. Three full-length infectious cDNA clones-rHN33-Lb, rHN33-La, and rHNGSLX-Lb-containing the FMDV O/CHN/Mya98/33-P strain leader proteins Lb, La, or the FMDV O/GSLX/2010 strain leader protein Lb, respectively, were constructed based on an established infectious clone r-HN rescued from FMDV O/HN/CHN/93 strain. After infecting pig kidney primary cells, rHN33-La showed higher replication efficiency than r-HN, and rHN33-Lb displayed better ability to resist host innate immunity than rHNGSLX-Lb. These results demonstrated that the inter-AUG region of FMDV strain O/CHN/Mya98/33-P leader protein must be involved in increasing viral replication efficiency. Additionally, the Lb of FMDV O/CHN/Mya98/33-P must be involve in increasing its ability to inhibit host innate immune response, and the distinctive amino acids G56 and/or R118 of FMDV leader protein may play essential roles in it.
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Affiliation(s)
- Shaodong Jiang
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Xingwen Bai
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Pinghua Li
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Meng Zhang
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Huifang Bao
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Pu Sun
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Zengjun Lu
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Yimei Cao
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Yingli Chen
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Dong Li
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Yuanfang Fu
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
| | - Zaixin Liu
- State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot and Mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, People's Republic of China
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Maree FF, Nsamba P, Mutowembwa P, Rotherham LS, Esterhuysen J, Scott K. Intra-serotype SAT2 chimeric foot-and-mouth disease vaccine protects cattle against FMDV challenge. Vaccine 2015; 33:2909-16. [DOI: 10.1016/j.vaccine.2015.04.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/10/2015] [Accepted: 04/15/2015] [Indexed: 10/23/2022]
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Genomic Changes in an Attenuated ZB Strain of Foot-and-Mouth Disease Virus Serotype Asia1 and Comparison with Its Virulent Parental Strain. Int J Genomics 2014; 2014:978609. [PMID: 25386556 PMCID: PMC4216683 DOI: 10.1155/2014/978609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 09/18/2014] [Accepted: 09/22/2014] [Indexed: 01/03/2023] Open
Abstract
The molecular basis of attenuation of foot-and-mouth disease virus (FMDV) serotype Asia1 ZB strain remains unknown. To understand the genetic changes of attenuation, we compared the entire genomes of three different rabbit-passaged attenuated ZB strains (ZB/CHA/58(att), ZBRF168, and ZBRF188) and their virulent parental strains (ZBCF22 and YNBS/58). The results showed that attenuation may be brought about by 28 common amino acid substitutions in the coding region, with one nucleotide point mutation in the 5′-untranslated region (5′-UTR) and another one in the 3′-UTR. In addition, a total of 21 nucleotides silent mutations had been found after attenuation. These substitutions, alone or in combination, may be responsible for the attenuated phenotype of the ZB strain in cattle. This will contribute to elucidation of attenuating molecular basis of the FMDV ZB strain.
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Foot-and-mouth disease virus virulence in cattle is co-determined by viral replication dynamics and route of infection. Virology 2014; 452-453:12-22. [PMID: 24606678 DOI: 10.1016/j.virol.2014.01.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/27/2013] [Accepted: 01/02/2014] [Indexed: 01/13/2023]
Abstract
Early events in the pathogenesis of foot-and-mouth disease virus (FMDV) infection in cattle were investigated through aerosol and intraepithelial lingual (IEL) inoculations of a cDNA-derived FMDV-A24 wild type virus (FMDV-WT) or a mutant derived from the same clone (FMDV-Mut). After aerosolization of FMDV-WT, primary infection sites had significantly greater quantities of FMDV, viral RNA, and type I/III interferon (IFN) activity compared to corresponding tissues from cattle infected with FMDV-Mut. Additionally, FMDV-WT-infected cattle had marked induction of systemic IFN activity in serum. In contrast, FMDV-Mut aerosol-infected cattle did not manifest systemic IFN response nor had viremia. Interestingly, IEL inoculation of FMDV-Mut in cattle restored the virulent phenotype and systemic IFN response. These data indicate that the attenuated phenotype in cattle is associated with decreased replicative efficiency, reflected by decreased innate response. However, attenuation is abrogated by bypassing the common primary infection sites, inducing accelerated viral replication at the inoculation site.
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Belsham GJ. Influence of the Leader protein coding region of foot-and-mouth disease virus on virus replication. J Gen Virol 2013; 94:1486-1495. [DOI: 10.1099/vir.0.052126-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The foot-and-mouth disease virus (FMDV) Leader (L) protein is produced in two forms, Lab and Lb, differing only at their amino-termini, due to the use of separate initiation codons, usually 84 nt apart. It has been shown previously, and confirmed here, that precise deletion of the Lab coding sequence is lethal for the virus, whereas loss of the Lb coding sequence results in a virus that is viable in BHK cells. In addition, it is now shown that deletion of the ‘spacer’ region between these two initiation codons can be tolerated. Growth of the virus precisely lacking just the Lb coding sequence resulted in a previously undetected accumulation of frameshift mutations within the ‘spacer’ region. These mutations block the inappropriate fusion of amino acid sequences to the amino-terminus of the capsid protein precursor. Modification, by site-directed mutagenesis, of the Lab initiation codon, in the context of the virus lacking the Lb coding region, was also tolerated by the virus within BHK cells. However, precise loss of the Lb coding sequence alone blocked FMDV replication in primary bovine thyroid cells. Thus, the requirement for the Leader protein coding sequences is highly dependent on the nature and extent of the residual Leader protein sequences and on the host cell system used. FMDVs precisely lacking Lb and with the Lab initiation codon modified may represent safer seed viruses for vaccine production.
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Affiliation(s)
- Graham J. Belsham
- National Veterinary Institute, Technical University of Denmark, Lindholm, 4771 Kalvehave, Denmark
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Li P, Bai X, Cao Y, Han C, Lu Z, Sun P, Yin H, Liu Z. Expression and stability of foreign epitopes introduced into 3A nonstructural protein of foot-and-mouth disease virus. PLoS One 2012; 7:e41486. [PMID: 22848509 PMCID: PMC3407237 DOI: 10.1371/journal.pone.0041486] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 06/21/2012] [Indexed: 11/19/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) is an aphthovirus that belongs to the Picornaviridae family and causes one of the most important animal diseases worldwide. The capacity of other picornaviruses to express foreign antigens has been extensively reported, however, little is known about FMDV. To explore the potential of FMDV as a viral vector, an 11-amino-acid (aa) HSV epitope and an 8 aa FLAG epitope were introduced into the C-terminal different regions of 3A protein of FMDV full-length infectious cDNA clone. Recombinant viruses expressing the HSV or FLAG epitope were successfully rescued after transfection of both modified constructs. Immunofluorescence assay, Western blot and sequence analysis showed that the recombinant viruses stably maintained the foreign epitopes even after 11 serial passages in BHK-21 cells. The 3A-tagged viruses shared similar plaque phenotypes and replication kinetics to those of the parental virus. In addition, mice experimentally infected with the epitope-tagged viruses could induce tag-specific antibodies. Our results demonstrate that FMDV can be used effectively as a viral vector for the delivery of foreign tags.
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Affiliation(s)
- Pinghua Li
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Xingwen Bai
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Yimei Cao
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Chenghao Han
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Zengjun Lu
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Pu Sun
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Hong Yin
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
- * E-mail: (HY); (ZXL)
| | - Zaixin Liu
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
- * E-mail: (HY); (ZXL)
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Whitt MA, Mire CE. Utilization of fluorescently-labeled tetracysteine-tagged proteins to study virus entry by live cell microscopy. Methods 2011; 55:127-36. [PMID: 21939769 DOI: 10.1016/j.ymeth.2011.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 09/01/2011] [Accepted: 09/02/2011] [Indexed: 10/24/2022] Open
Abstract
Viruses exploit cellular machinery to gain entry and initiate their replication cycle within host cells. The development of methods to visualize virus entry in live cells has provided new insights to the cellular processes involved in virus entry and the intracellular locations where viral payloads are deposited. The use of fluorescently labeled virus and high-resolution microscopy is currently the method of choice to study virus entry in live cells. While fluorescent protein fusions (e.g. viral proteins fused to GFP) have been used, the labeling of viral proteins that contain a small tetracysteine (tc) tag with biarsenical fluorescent compounds (e.g. FlAsH, ReAsH, Lumio-x) offers several advantages over conventional xFP-fusion constructs. This article describes methods for generating fluorescently labeled viruses encoding tc-tagged proteins that are suitable for the study of virus entry in live cells by fluorescence microscopy. Critical parameters required to quantify fluorescence signals from the labeled, tc-tagged proteins in individual virus particles during the entry process and the subsequent fate of the labeled viral proteins after virus uncoating are also described.
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Affiliation(s)
- Michael A Whitt
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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