|
1
|
Cao H, Deng H, Wang Y, Liu D, Li L, Li M, Peng D, Dai J, Li J, Qiu H, Li S. The Distal Promoter of the B438L Gene of African Swine Fever Virus Is Responsible for the Transcription of the Alternatively Spliced B169L. Viruses 2024; 16:1058. [PMID: 39066221 PMCID: PMC11281499 DOI: 10.3390/v16071058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/20/2024] [Accepted: 06/28/2024] [Indexed: 07/28/2024] Open
Abstract
The B169L protein (pB169L) of African swine fever virus (ASFV) is a structural protein with an unidentified function during the virus replication. The sequences of the B169L gene and the downstream B438L gene are separated by short intergenic regions. However, the regulatory mode of the gene transcription remains unknown. Here, we identified two distinct promoter regions and two transcription start sites (TSSs) located upstream of the open reading frame (ORF) of B438L. Using the promoter reporter system, we demonstrated that the cis activity of the ORF proximal promoter exhibited significantly higher levels compared with that of the distal promoter located in the B169L gene. Furthermore, transfection with the plasmids with two different promoters for B438L could initiate the transcription and expression of the B438L gene in HEK293T cells, and the cis activity of the ORF proximal promoter also displayed higher activities compared with the distal promoter. Interestingly, the B438L distal promoter also initiated the transcription of the alternatively spliced B169L mRNA (B169L mRNA2) encoding a truncated pB169L (tpB169L) (amino acids 92-169), and the gene transcription efficiency was increased upon mutation of the initiation codon located upstream of the alternatively spliced B169L gene. Taken together, we demonstrated that the distal promoter of B438L gene initiates the transcription of both the B438L mRNA and B169L mRNA2. Comprehensive analysis of the transcriptional regulatory mode of the B438L gene is beneficial for the understanding of the association of B438L protein and pB169L and the construction of the gene-deleted ASFV.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Huaji Qiu
- State Key Laboratory for Animal Disease Prevention and Control, National African Swine Fever Para-Reference Laboratory, National High-Containment Facilities for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China; (H.C.); (H.D.); (Y.W.); (D.L.); (L.L.); (M.L.); (D.P.); (J.D.); (J.L.)
| | - Su Li
- State Key Laboratory for Animal Disease Prevention and Control, National African Swine Fever Para-Reference Laboratory, National High-Containment Facilities for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China; (H.C.); (H.D.); (Y.W.); (D.L.); (L.L.); (M.L.); (D.P.); (J.D.); (J.L.)
| |
Collapse
|
|
2
|
Zhou Y, Zhang J, Sun H, Tao D, Xu B, Han X, Ren R, Ruan J, Steinaa L, Hemmink JD, Han J, Li X, Xu J, Zhao S, Xie S, Zhao C. Sensitive and Specific Exonuclease III-Assisted Recombinase-Aided Amplification Colorimetric Assay for Rapid Detection of Nucleic Acids. ACS Synth Biol 2023; 12:2877-2886. [PMID: 37729559 DOI: 10.1021/acssynbio.3c00137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The development of a contamination-free and on-site nucleic acid detection platform with high sensitivity and specificity but low-cost for the detection of pathogenic nucleic acids is critical for infectious disease diagnosis and surveillance. In this study, we combined the recombinase-aided amplification (RAA) with the exonuclease III (Exo III)-assisted signal amplification into a platform for sensitive and specific detection of nucleic acids of African swine fever virus (ASFV). We found that this platform enabled a naked eye visual detection of ASFV at a detection limit as low as 2 copies/μL in 30 min. As expected, no cross-reactivity was observed with other porcine viruses. In addition, to avoid aerosol contamination, a one-tube RAA-Exo III colorimetric assay was also established for the accurate detection of ASFV in clinical samples. Taken together, we developed a rapid, instrument-free, and low-cost Exo III-assisted RAA colorimetric-assay-based nucleic acid detection platform.
Collapse
Affiliation(s)
- Yuan Zhou
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Jinfu Zhang
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Haowen Sun
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Dagang Tao
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Bingrong Xu
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Xiaosong Han
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Ruimin Ren
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Jinxue Ruan
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Lucilla Steinaa
- Animal and Human Health Program, Biosciences, International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Johanneke D Hemmink
- Animal and Human Health Program, Biosciences, International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Jianlin Han
- CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100193, P. R. China
- Biosciences, International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Xinyun Li
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, P. R. China
- Hubei Hongshan Laboratory, Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430070, P. R. China
| | - Jing Xu
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Shuhong Zhao
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, P. R. China
- Hubei Hongshan Laboratory, Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430070, P. R. China
| | - Shengsong Xie
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, P. R. China
- Hubei Hongshan Laboratory, Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430070, P. R. China
| | - Changzhi Zhao
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, P. R. China
| |
Collapse
|
|
3
|
Shi K, Zhao K, Wei H, Zhou Q, Shi Y, Mo S, Long F, Hu L, Feng S, Mo M. Triplex Crystal Digital PCR for the Detection and Differentiation of the Wild-Type Strain and the MGF505-2R and I177L Gene-Deleted Strain of African Swine Fever Virus. Pathogens 2023; 12:1092. [PMID: 37764900 PMCID: PMC10534775 DOI: 10.3390/pathogens12091092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023] Open
Abstract
African swine fever (ASF) is a severe and highly contagious viral disease that affects domestic pigs and wild boars, characterized by a high fever and internal bleeding. The disease is caused by African swine fever virus (ASFV), which is prevalent worldwide and has led to significant economic losses in the global pig industry. In this study, three pairs of specific primers and TaqMan probes were designed for the ASFV B646L, MGF505-2R and I177L genes. After optimizing the reaction conditions of the annealing temperature, primer concentration and probe concentration, triplex crystal digital PCR (cdPCR) and triplex real-time quantitative PCR (qPCR) were developed for the detection and differentiation of the wild-type ASFV strain and the MGF505-2R and/or I177L gene-deleted ASFV strains. The results indicate that both triplex cdPCR and triplex qPCR were highly specific, sensitive and repeatable. The assays could detect only the B646L, MGF505-2R and I177L genes, without cross-reaction with other swine viruses (i.e., PRRSV, CSFV, PCV2, PCV3, PEDV, PDCoV and PRV). The limit of detection (LOD) of triplex cdPCR was 12 copies/reaction, and the LOD of triplex qPCR was 500 copies/reaction. The intra-assay and inter-assay coefficients of variation (CVs) for repeatability and reproducibility were less than 2.7% for triplex cdPCR and less than 1.8% for triplex qPCR. A total of 1510 clinical tissue samples were tested with both methods, and the positivity rates of ASFV were 14.17% (214/1510) with triplex cdPCR and 12.98% (196/1510) with triplex qPCR, with a coincidence rate of 98.81% between the two methods. The positivity rate for the MGF505-2R gene-deleted ASFV strains was 0.33% (5/1510), and no I177L gene-deleted ASFV strain was found. The results indicate that triplex cdPCR and triplex qPCR developed in this study can provide rapid, sensitive and accurate methods for the detection and differentiation of the ASFV B646L, MGF505-2R and I177L genes.
Collapse
Affiliation(s)
- Kaichuang Shi
- College of Animal Science and Technology, Guangxi University, Nanning 530005, China; (K.Z.); (Y.S.)
- Guangxi Center for Animal Disease Control and Prevention, Nanning 530001, China; (H.W.); (Q.Z.); (S.M.); (F.L.); (L.H.); (S.F.)
| | - Kang Zhao
- College of Animal Science and Technology, Guangxi University, Nanning 530005, China; (K.Z.); (Y.S.)
| | - Haina Wei
- Guangxi Center for Animal Disease Control and Prevention, Nanning 530001, China; (H.W.); (Q.Z.); (S.M.); (F.L.); (L.H.); (S.F.)
| | - Qingan Zhou
- Guangxi Center for Animal Disease Control and Prevention, Nanning 530001, China; (H.W.); (Q.Z.); (S.M.); (F.L.); (L.H.); (S.F.)
| | - Yuwen Shi
- College of Animal Science and Technology, Guangxi University, Nanning 530005, China; (K.Z.); (Y.S.)
| | - Shenglan Mo
- Guangxi Center for Animal Disease Control and Prevention, Nanning 530001, China; (H.W.); (Q.Z.); (S.M.); (F.L.); (L.H.); (S.F.)
| | - Feng Long
- Guangxi Center for Animal Disease Control and Prevention, Nanning 530001, China; (H.W.); (Q.Z.); (S.M.); (F.L.); (L.H.); (S.F.)
| | - Liping Hu
- Guangxi Center for Animal Disease Control and Prevention, Nanning 530001, China; (H.W.); (Q.Z.); (S.M.); (F.L.); (L.H.); (S.F.)
| | - Shuping Feng
- Guangxi Center for Animal Disease Control and Prevention, Nanning 530001, China; (H.W.); (Q.Z.); (S.M.); (F.L.); (L.H.); (S.F.)
| | - Meilan Mo
- College of Animal Science and Technology, Guangxi University, Nanning 530005, China; (K.Z.); (Y.S.)
| |
Collapse
|
|
4
|
Mao G, Luo X, Ye S, Wang X, He J, Kong J, Dai J, Yin W, Ma Y. Fluorescence and Colorimetric Analysis of African Swine Fever Virus Based on the RPA-Assisted CRISPR/Cas12a Strategy. Anal Chem 2023; 95:8063-8069. [PMID: 37167072 DOI: 10.1021/acs.analchem.3c01033] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
It is well-established that different detection modes are necessary for corresponding applications, which can effectively reduce matrix interference and improve the detection accuracy. Here, we reported a magnetic separation method based on recombinase polymerase amplification (RPA)-assisted clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a for dual-mode analysis of African swine fever virus (ASFV) genes, including colorimetry and fluorescence. The ASFV gene was selected as the initial RPA template to generate the amplicon. The RPA amplicon was then recognized by CRISPR-associated RNA (crRNA), activating the trans-cleavage activity of Cas12a and leading to the nonspecific cleavage of ssDNA as well as a significant release of alkaline phosphatase (ALP) in the ALP-ssDNA modified magnetic bead. The released ALP can catalyze para-nitrophenyl phosphate to generate para-nitrophenol, resulting in substantial changes in absorbance and fluorescence, both of which can be used for detection with the naked eye. This strategy allows the sensitive detection of ASFV DNA, with a 20 copies/mL detection limit; no cross-reactivity with other viruses was observed. A good linear relationship was obtained in serum. In addition, this sensor displayed 100% specificity and sensitivity for clinical sample analysis. This method integrates the high sensitivity of fluorescence with easy readout of colorimetry and enables a simple, low-cost, and highly sensitive dual-mode detection of viral nucleic acid, thereby providing a broad prospect for the practical application in the diagnosis of virus infection.
Collapse
Affiliation(s)
- Guobin Mao
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xing Luo
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Silu Ye
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xun Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jilie Kong
- Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, 2005 Songhu Road, Shanghai 200433, China
| | - Junbiao Dai
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yingxin Ma
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| |
Collapse
|
|
5
|
Li Z, Chen W, Qiu Z, Li Y, Fan J, Wu K, Li X, Zhao M, Ding H, Fan S, Chen J. African Swine Fever Virus: A Review. Life (Basel) 2022; 12:1255. [PMID: 36013434 PMCID: PMC9409812 DOI: 10.3390/life12081255] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/29/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
African swine fever (ASF) is a viral disease with a high fatality rate in both domestic pigs and wild boars. ASF has greatly challenged pig-raising countries and also negatively impacted regional and national trade of pork products. To date, ASF has spread throughout Africa, Europe, and Asia. The development of safe and effective ASF vaccines is urgently required for the control of ASF outbreaks. The ASF virus (ASFV), the causative agent of ASF, has a large genome and a complex structure. The functions of nearly half of its viral genes still remain to be explored. Knowledge on the structure and function of ASFV proteins, the mechanism underlying ASFV infection and immunity, and the identification of major immunogenicity genes will contribute to the development of an ASF vaccine. In this context, this paper reviews the available knowledge on the structure, replication, protein function, virulence genes, immune evasion, inactivation, vaccines, control, and diagnosis of ASFV.
Collapse
Affiliation(s)
- Zhaoyao Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Wenxian Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Zilong Qiu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Yuwan Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Jindai Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Keke Wu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Xiaowen Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Mingqiu Zhao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Hongxing Ding
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Shuangqi Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Jinding Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| |
Collapse
|
|
6
|
The Development of a Multiplex Real-Time Quantitative PCR Assay for the Differential Detection of the Wild-Type Strain and the MGF505-2R, EP402R and I177L Gene-Deleted Strain of the African Swine Fever Virus. Animals (Basel) 2022; 12:ani12141754. [PMID: 35883301 PMCID: PMC9311895 DOI: 10.3390/ani12141754] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary African swine fever (ASF) was first reported in August 2018 in China, and the naturally gene-deleted ASFV strain was first identified in 2020 in this country. The vaccine candidates that deleted some virulent genes from the virulent parental strains have also been reported in many countries. To differentiate the wild-type and gene-deleted ASFV strains, four pairs of specific primers and TaqMan probes targeting the ASFV B646L (p72), I177L, MGF505-2R and EP402R (CD2v) genes were designed. After optimizing the reaction conditions, a multiplex real-time qPCR assay for the differential detection of the wild-type and gene-deleted ASFV strains was developed. The assay was further used to test 4239 clinical samples, and 534 samples were positive for ASFV, of which 30 samples lacked B646L, I177L, MGF505-2R and/or EP402R genes. The assay showed high specificity, sensitivity and repeatability, and it provided a reliable method for evaluating ASFV in clinical samples. Abstract African swine fever virus (ASFV) causes African swine fever (ASF), a devastating hemorrhagic disease of domestic pigs and wild boars. Currently, the MGF505R, EP402R (CD2v) and I177L gene-deleted ASFV strains were confirmed to be the ideal vaccine candidate strains. To develop an assay for differentiating the wild-type and gene-deleted ASFV strains, four pairs of specific primers and TaqMan probes targeting the ASFV B646L (p72), I177L, MGF505-2R and EP402R (CD2v) genes were designed. A multiplex real-time qPCR assay for the differential detection of the wild-type and gene-deleted ASFV strains was developed after optimizing the reaction conditions, including the annealing temperature, primer concentration and probe concentration. The results showed that the multiplex real-time qPCR assay can specifically test the ASFV B646L (p72), I177L, MGF505-2R and EP402R (CD2v) genes with a limit of detection (LOD) of 32.1 copies/μL for the B646L (p72) gene, and 3.21 copies/μL for the I177L, MGF505-2R and EP402R (CD2v) genes. However, the assay cannot test for the classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), porcine circovirus type 2 (PCV2), PCV3 and pseudorabies virus (PRV). The assay demonstrated good repeatability and reproducibility with coefficients of variation (CV) less than 1.56% for both the intra- and inter-assay. The assay was used to test 4239 clinical samples, and the results showed that 12.60% (534/4239) samples were positive for ASFV, of which 10 samples lacked the EP402R gene, 6 samples lacked the MGF505-2R gene and 14 samples lacked the EP402R and MGF505-2R genes. The results indicated that the multiplex real-time qPCR developed in this study can provide a rapid, sensitive and specific diagnostic tool for the differential detection of the ASFV B646L, I177L, MGF505-2R and EP402R genes.
Collapse
|