Gene synthesis is an enabling technology that supports the development of synthetic biology. The existing approaches for de novo gene synthesis generally have tedious operation, low efficiency, high error rates, and limited product lengths, being difficult to support the huge demand of synthetic biology. The assembly and error correction are the keys in gene synthesis. This study first designed the oligonucleotide sequences by reasonably splitting the virus genome of approximately 10 kb by balancing the parameters of sequence design software ability, PCR amplification ability, and assembly enzyme assembly ability. Then, two-step PCR was performed with high-fidelity polymerase to complete the de novo synthesis of 3.0 kb DNA fragments, and error correction reactions were performed with T7 endonuclease Ⅰ for the products from different stages of PCR. Finally, the virus genome was assembled by 3.0 kb DNA fragments from de novo synthesis and error correction and then sequenced. The experimental results showed that the proposed method successfully produced the DNA fragment of about 10 kb and reduced the probability of large fragment mutations during the assembly process, with the lowest error rate reaching 0.36 errors/kb. In summary, this study developed an efficient de novo method for synthesizing a viral genome of about 10 kb with T7 endonuclease Ⅰ-mediated error correction. This method enabled the synthesis of a 10 kb viral genome in one day and the correct plasmid of the viral genome in five days. This study optimized the de novo gene synthesis process, reduced the error rate, simplified the synthesis and assembly steps, and reduced the cost of viral genome assembly.
Genome, Viral/genetics* ; Polymerase Chain Reaction/methods* ; DNA, Viral/genetics* ; Bacteriophage T7/enzymology* ; Synthetic Biology/methods*

Foot-and-mouth disease (FMD) is one of the major animal infectious diseases in the world. All cloven-hoofed animals are susceptible to FMD. Vaccination is still the first choice for the prevention and control of FMD. mRNA vaccines can be rapidly designed, synthesized, and produced on a large scale in vitro, and they can induce effective protective immune responses, demonstrating the advantages of rapid development, easy preparation, and low biosafety risks. The design of untranslated regions is a key to enhancing the expression and efficacy of mRNA vaccines. In order to generate an efficient FMD mRNA vaccine, we designed three FMD P12A3C expression vectors with different untranslated regions and synthesized corresponding mRNAs. By comparing expression efficiency of these vectors and their mRNAs at different time points and in different cell lines, we found that the mRNA P12A3C-UTR3 had the best expression and universality. This study laid a foundation for the development of mRNA vaccines against FMD and provided a theoretical basis for the optimal sequence design of efficient mRNA.
Foot-and-Mouth Disease Virus/genetics* ; Animals ; RNA, Messenger/biosynthesis* ; Foot-and-Mouth Disease/immunology* ; Antigens, Viral/biosynthesis* ; Viral Vaccines/biosynthesis* ; Genetic Vectors/genetics* ; Cell Line ; Vaccines, DNA/immunology*

Geminiviruses cause substantial crop yield losses worldwide. The replication initiator protein (Rep) encoded by geminiviruses is indispensable for geminiviral replication. The Rep protein encoded by beet severe curly top virus (BSCTV, genus Curtovirus, family Geminiviridae) induces VARIANT IN METHYLATION 5 (VIM5) expression in Arabidopsis leaves upon BSCTV infection. VIM5 functions as a ubiquitination-related E3 ligase to promote the proteasomal degradation of methyltransferases, resulting in reduction of methylation levels in the BSCTV C2-3 promoter. However, the specific domains of Rep responsible for VIM5 induction remain poorly characterized. Although Rep proteins from several geminiviruses act as viral suppressors of RNA silencing (VSRs), whether BSCTV Rep also possesses VSR activity remains to be illustrated. In this study, we employed a transient expression system in the 16c-GFP transgenic and the wild-type Nicotiana benthamiana plants to analyze the VSR and the VIM5-inducing activities of different truncated Rep proteins haboring distinct domains. We found that the N-terminal domain (amino acids 1-180) of Rep suppressed GFP silencing in 16c-GFP transgenic N. benthamiana leaves. The minimal N-terminal fragment (amino acids 1-104) induced VIM5 expression upon co-infiltration, while C-terminal truncations lacked VIM5-inducing activity. Our results indicate that the N-terminal domain of Rep encoded by BSCTV mediates the suppression of RNA silencing and induces VIM5 expression. Thus, our findings contribute to a better understanding of interactions between geminiviral Rep and plant hosts.
Geminiviridae/genetics* ; Nicotiana/metabolism* ; Arabidopsis/metabolism* ; RNA Interference ; Viral Proteins/metabolism* ; Arabidopsis Proteins/metabolism* ; Plants, Genetically Modified/metabolism* ; Protein Domains ; Plant Diseases/virology* ; Methyltransferases/metabolism* ; Ubiquitin-Protein Ligases/metabolism* ; DNA Helicases/genetics*

OBJECTIVES: Long-term hepatitis B virus (HBV) infection can cause recurrent inflammation in the liver, and then develop into liver fibrosis, cirrhosis, and liver cancer. The hepatic pathological change is one of the important criteria for guiding antiviral therapy in patients with chronic hepatitis B (CHB). Due to the limitations of liver biopsy, it is necessary to find valuable non-invasive indicators to evaluate the hepatic pathological changes in CHB patients and guide the antiviral therapy. This study aims to analyze the clinical characteristics of different pathological changes in CHB patients, and to explore the factors influnencing the degree of liver inflammation and fibrosis in CHB patients with normal alanine aminotransferase (ALT). METHODS: This retrospective study was conducted on 310 CHB patients. Liver biopsy was performed in all these patients. The clinical data of the patients were collected. The liver biopsy pathological results were used as the gold standard to analyze the relationship between clinical indicators and liver pathological changes. Then CHB patients with normal ALT were screened, and the independent factors influencing the degree of liver inflammation and fibrosis were explored. RESULTS: Among the 310 patients with CHB, there were 249 (80.3%) patients with significant liver inflammation [liver inflammation grade (G) ≥2] and 119 (38.4%) patients with significant liver fibrosis [liver fibrosis stage (S) ≥2]. The results of univariate analysis of total samples showed that the ALT, γ-glutamyl transferase, alkaline phosphatase, and HBV DNA were related to the significant liver pathological changes. Among the 132 CHB patients with normal ALT, the patients with liver pathology G/S≥2, G≥2, and S≥2 were 80.3% (106/132), 68.2% (90/132), and 43.2% (57/132), respectively. The results showed that the independent influencing factor of significant liver inflammation was HBV DNA>2 000 U/mL (OR=3.592, 95% CI 1.534 to 8.409), and the independent influencing factors of significant liver fibrosis were elevated alkaline phosphatase level (OR=1.022, 95% CI 1.002 to 1.043), decreased platelet count (OR=0.990, 95% CI 0.982 to 0.998), and positive in hepatitis B e antigen (HBeAg) (OR=14.845, 95% CI 4.898 to 44.995). According to the multivariate analysis, a diagnostic model for significant liver fibrosis in CHB patients with normal ALT was established, and the area under the receiver operating characteristic curve was 0.844 (95% CI 0.779 to 0.910). CONCLUSIONS The liver pathological changes should be evaluated in combination with different clinical indicators. A considerable number of CHB patients with normal ALT still have significant liver pathological changes, which need to be identified and treated with antiviral therapy in time. Among them, HBV DNA>2 000 U/mL suggests the significant liver inflammation, and the diagnostic model for significant liver fibrosis based on alkaline phosphatase, platelet count, and HBeAg can help to evaluate the degree of liver fibrosis.
Humans ; Hepatitis B, Chronic/complications* ; Hepatitis B e Antigens/therapeutic use* ; Alkaline Phosphatase ; DNA, Viral ; Retrospective Studies ; Fibrosis ; Hepatitis B virus/genetics* ; Liver Cirrhosis/etiology* ; Inflammation/drug therapy* ; Antiviral Agents/therapeutic use* ; Alanine Transaminase

Objective: To determine the optimal cutoff value of Epstein-Barr virus (EBV) DNA load that can assist in the diagnosis of post-transplant lymphoproliferative disease (PTLD) after haploidentical hematopoietic stem cell transplantation (haplo-HSCT) . Methods: The data of patients with EBV infection after haplo-HSCT from January to December 2016 were retrospectively analyzed. Through constructing the receiver operating characteristic (ROC) curve and calculating the Youden index to determine the cutoff value of EBV-DNA load and its duration of diagnostic significance for PTLD. Results: A total of 94 patients were included, of whom 20 (21.3% ) developed PTLD, with a median onset time of 56 (40-309) d after transplantation. The median EBV value at the time of diagnosis of PTLD was 70,400 (1,710-1,370,000) copies/ml, and the median duration of EBV viremia was 23.5 (4-490) d. Binary logistic regression was used to analyze the peak EBV-DNA load (the EBV-DNA load at the time of diagnosis in the PTLD group) and duration of EBV viremia between the PTLD and non-PTLD groups. The results showed that the difference between the two groups was statistically significant (P=0.018 and P=0.001) . The ROC curve was constructed to calculate the Youden index, and it was concluded that the EBV-DNA load ≥ 41 850 copies/ml after allogeneic hematopoietic stem cell transplantation had diagnostic significance for PTLD (AUC=0.847) , and the sensitivity and specificity were 0.611 and 0.932, respectively. The duration of EBV viremia of ≥20.5 d had diagnostic significance for PTLD (AUC=0.833) , with a sensitivity and specificity of 0.778 and 0.795, respectively. Conclusion: Dynamic monitoring of EBV load in high-risk patients with PTLD after haplo-HSCT and attention to its duration have important clinical significance, which can help clinically predict the occurrence of PTLD in advance and take early intervention measures.
Humans ; Epstein-Barr Virus Infections/diagnosis* ; Herpesvirus 4, Human/genetics* ; Retrospective Studies ; Viremia ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Lymphoproliferative Disorders/etiology* ; DNA, Viral ; Viral Load

Objective: This article investigated the clinical characteristics and distribution of drug resistance mutation sites in HBV RT region of hepatitis B infected patients. Methods: Retrospective analysis was made on 1 948 patients with HBV infection, who had been tested for NAs resistance mutation and had a medical history of NAs in the Laboratory Department of the Fifth Medical Center of the PLA General Hospital from January 2020 to December 2021. Basic clinical information and drug resistance related mutation information were recorded. Meanwhile, the serological index data of hepatitis B were collected. Drug resistance gene mutant group and non-mutated group were grouped according to whether the drug resistance genes had a mutation in HBV RT region, and the clinical characteristics and genotype distribution of the two groups were statistically analyzed. The pattern of drug resistance gene mutation, number of mutation sites, drug resistance type and mutation of NAs resistance-related sites were analyzed in 917 patients with drug resistance gene mutation in HBV RT region. χ² Inspection was used for counting data. Meanwhile, two independent samples t-test and Wilcoxon rank sum test were used for measurement data. Results: Among the 1 948 patients with chronic HBV infection, 917 patients had drug resistance gene mutation in RT region (47.07%). The proportion of patients with acute hepatitis B and CHB in HBV RT resistance gene mutant group was lower than that in the non-mutated group, while the proportion of patients with HBV-related cirrhosis was higher than that in the non-mutated group, these differences were statistically significant. Compared with the non-mutated group in HBV RT region, the age, the positive rates of HBeAg and HBV DNA, and HBV DNA load of these patients were increased in drug resistance gene mutant group, these differences were statistically significant. Genotypes of patients in both groups were dominated by C, followed by B and D. The proportion of patients with genotype C in HBV RT drug resistance gene mutant group was higher than that of non-mutated group, the difference was statistically significant. There were 53 gene mutation patterns in 917 patients with drug resistance gene mutation in HBV RT region, and the main pattern was rtL180M+rtM204V+rtS202G (9.70%). The mutation sites were dominated by 3 (20.74%). There were 5 types of drug resistance, LAM+Ldt (21.25%) was the most. Among the 18 sites that were clearly associated with LAM, ADV, ETV and Ldt resistance in the HBV RT region, 14 sites were mutated, and the most common mutation sites were rtL180M, rtM204V, rtM204 and rtS202G. what's more, the proportion of patients with NAs drug resistance was LAM>Ldt>ETV>ADV. Conclusion: In order to prevent adverse consequences of this study such as disease recurrence or disease progression caused by HBV drug resistance, HBV infected patients, who have long-term use of NAs antiviral therapy, should monitor the level of HBV DNA and drug resistance genes in HBV RT region in order to optimize the treatment plan in time or guide individualized treatment.
Humans ; Hepatitis B virus/genetics* ; Hepatitis B, Chronic ; Antiviral Agents/therapeutic use* ; DNA, Viral/therapeutic use* ; Retrospective Studies ; Mutation ; Drug Resistance, Viral/genetics* ; Lamivudine/therapeutic use*

Humans ; Squamous Cell Carcinoma of Head and Neck ; RNA, Messenger ; Immunohistochemistry ; Papillomavirus Infections/diagnosis* ; Oncogene Proteins, Viral/genetics* ; Head and Neck Neoplasms ; Cyclin-Dependent Kinase Inhibitor p16 ; Papillomaviridae ; Papillomavirus E7 Proteins/genetics* ; DNA, Viral

The resolution of the hepatitis C issue has raised expectations for a chronic hepatitis B cure, driving the industry to expand investment in research and development efforts to strengthen functional cure strategies. These strategies have a wide variety of types, and the published research findings are heterogeneous. The theoretical analysis of these strategies is of great significance for determining prioritized research orientations as well as sensibly allocating research and development resources. However, due to a paucity of necessary conceptual models, current theoretical analysis has not been able to unify various therapeutic strategies into a proper theoretical framework. In view of the fact that the decrease in the quantity of cccDNA is an inevitable core event accompanied by the process of functional cure, this paper intends to analyze several chronic hepatitis B cure strategies using cccDNA dynamics as a framework. Furthermore, there are currently few studies on the dynamics of the cccDNA field, hoping that this article can promote recognition and research in this field.
Humans ; Hepatitis B virus/genetics* ; Hepatitis B, Chronic/drug therapy* ; Antiviral Agents/therapeutic use* ; Virus Replication ; DNA, Circular/therapeutic use* ; DNA, Viral/genetics* ; Hepatitis B/drug therapy*

Humans ; Hepatitis B Surface Antigens ; Hepatitis B/drug therapy* ; Hepatitis B virus/genetics* ; Antiviral Agents/therapeutic use* ; Hepatitis B, Chronic/diagnosis* ; DNA, Viral

Objective: To understand ten-year changes in clinical characteristics and antiviral treatment patterns of chronic hepatitis B in China. Methods: Patients with chronic HBV infection:demographic, virologic, hematologic, blood biochemistry, and antiviral treatment data were extracted from the China Registry of Hepatitis B (CR-HepB) database between 2012 and 2022 for descriptive statistics and change trend analysis. Multiple group comparisons were conducted using the Kruskal Wallis H test, while counting data was compared between groups using χ (2) test. Results: A total of 180 012 patients with chronic HBV infection were included, with a median age of 40 years old, and a male proportion accounting for 60.2%. The HBeAg positive rate was 43.3%. Over time, the median age of new patients each year increased from 39 to 47 years, while the HBeAg positive rate decreased from 51.3% to 32.8%. The initial diagnosis of patients was mainly CHB (71.4%), followed by hepatitis B cirrhosis (11.8%), inactive HBsAg carrier status (10.6%), and chronic HBV carrier status (6.2%). Among the newly registered patients every year from 2012 to 2022, the proportion of hepatitis B cirrhosis remained stable, but after 2019, the proportion of CHB increased and the proportion of other diagnoses decreased. The proportion of patients with cirrhosis increased with age in different age groups, with 3.5%, 19.3%, and 30.4% in the < 40, 40-69, and≥70 age groups, respectively. The proportion of women in patients with cirrhosis also increased with age, from 16.1% in those < 30 years old to 44.3% in those≥80 years old. From 2012 to 2022, the proportion of patients receiving first-line nucleos(t)ide analog antiviral treatment increased year by year, from 51.0% in 2012-2013 to 99.8% in 2022. Conclusion: The CR-HepB registration data reflect the changes in clinical characteristics and antiviral treatment patterns in patients with chronic HBV infection in China over the past ten years and can thus provide a reference to promote hepatitis B diagnosis and treatment practice, as well as scientific research.
Humans ; Male ; Female ; Adult ; Aged, 80 and over ; Antiviral Agents/therapeutic use* ; Hepatitis B, Chronic/epidemiology* ; Hepatitis B e Antigens ; Hepatitis B/drug therapy* ; Hepatitis B Surface Antigens ; Hepatitis A ; Liver Cirrhosis/drug therapy* ; China/epidemiology* ; Registries ; Hepatitis B virus/genetics* ; DNA, Viral