Establishment of transgenic mouse harboring hepatitis B virus (adr subtype) genomes

INTRODUCTIONHepatitis B virus (HBV) belongs to the group ofhepatovirus, a major pathogen of human acute andchronic hepatitis B[1 4], which has a very closeassociation with human hepatocellular carcinoma(HCC)[5-8], For example, a statistical data from ahospital in Shanghai showed that 80% of HCCpatients were positive for HBsAg ( personalcommunication).

PCR restriction fragment length polymorphism in detection of YMDD variants of viral polymerase in hepatitis B virus patients treated with lamivudine

Objective: To analyse the emergence of YMDD motif(tyrosine-methionine-aspartate-aspartate) variants inpatients with hepatitis B treated with lamivudine.Methods: The amino acid substitution from methio-nine or isoleucine at the YMDD motif at the HBVpolymerase gene is a main mutation resistant to lami-vudine treatment. Generated from a fragment of do-main C of the polymerase gene, patients HBV DNA,which had been positive previously became positive a-gain ever since it had been negative during lamivudi-ne therapy. Variants were detected by cleavage of theproducts of the three PCRs with following enzymes:FokI, SspI, Alw441. The results of PCR-RELP wereanalysed by 8. 4% polypropylene acidemide gel elec-trophoresis. PCR-RFLP assay was compared to di-rect sequencing.Results: HBV DNA was positive again in 33 patientsand positive for one year in 2 patients. YMDD vari-ants were detected in serum 14 of 35 patients, YIDDvariants in 4, YVDD variants in 6, and YI/MDD va-riants in 1; all were in concordance with the resultsof direct sequencing. The samples of other 3 patientsshowed YI/VDD mutations, as shown by direct se-quencing. The results of PCR-RFLP assay of themixed sera of YIDD and YVDD variants were similarto those sera of YI/VDD variants.Conclusion: PCR-RFLP is suitable for rapid detec-tion of YMDD variants of viral polymerase in hepati-tis B virus patients treated with lamivudine.

Hepatitis B virus pre-S/S variants in liver diseases

Chronic hepatitis B is a global health problem. The clinical outcomes of chronic hepatitis B infection include asymptomatic carrier state, chronic hepatitis(CH), liver cirrhosis(LC), and hepatocellular carcinoma(HCC). Because of the spontaneous error rate inherent to viral reverse transcriptase, the hepatitis B virus(HBV) genome evolves during the course of infection under the antiviral pressure of host immunity. The clinical significance of pre-S/S variants has become increasingly recognized in patients with chronic HBV infection. Pre-S/S variants are often identified in hepatitis B carriers with CH, LC, and HCC, which suggests that these naturally occurring pre-S/S variants may contribute to the development of progressive liver damage and hepatocarcinogenesis. This paper reviews the function of the pre-S/S region along with recent findings related to the role of pre-S/S variants in liver diseases. According to the mutation type, five pre-S/S variants have been identified: pre-S deletion, pre-S point mutation, pre-S1 splice variant, C-terminus S point mutation, and pre-S/S nonsense mutation. Their associations with HBV genotype and the possible pathogenesis of pre-S/S variants are discussed. Different pre-S/S variants cause liver diseases through different mechanisms. Most cause the intracellular retention of HBV envelope proteins and induction of endoplasmic reticulum stress, which results in liver diseases. Pre-S/S variants should be routinely determined in HBV carriers to help identify individuals who may be at a high risk of less favorable liver disease progression. Additional investigations are required to explore the molecular mechanisms of the pre-S/S variants involved in the pathogenesis of each stage of liver disease.

Gene heterogeneity of hepatitis B virus isolates from patients with severe hepatitis B

BACKGROUND: The pathogenesis of severe hepatitis B remains unknown. Reports have indicated that hepatitis B virus (HBV) mutations are important factors in the pathogenesis of this disease. This study was to investigate the genetic heterogeneity of HBV strains from serum samples of patients with fulminant hepatitis B. METHODS: Full-length HBV genomes from 4 patients with severe hepatitis B were cloned and sequenced to observe mutations in every open reading-frame ( ORF). Serum samples of another 25 patients with severe hepatitis B, 30 patients with chronic hepatitis B, and 25 HBV carriers were collected for sequencing and comparison of mutations in preS2, preC and core promoter regions. RESULTS: Of 4 HBV full-length genome sequences, 3 had a G to A mutation at nucleotide A1896 in the preC region and 1 had double mutations of T1762-A1764 in the core promoter region. The 4 sequences showed mutations in the known B or T cell epitopes of the preS2 and C regions. For the other 3 groups, more mutations were seen in the preS2 region in the HBV isolates from the patients with severe hepatitis B than those from the patients with chronic hepatitis B and HBV carriers (P <0.01). There was a significant difference of mutations in the T cell epitope region of preS2 between the patients with severe hepatitis B and those with chronic hepatitis B or HBV carriers (P <0.01). In the preC and core promoter regions, the mutation frequencies of T1653 and C1753 were 48.0% and 24.0% respectively in the patients with severe hepatitis B, but none of these mutations were observed in the patients with chronic hepatitis B group or HBV carriers (P <0.01). The mutation frequency of T1762-A1764 was 76.0% in the patients with severe hepatitis B, 40.0% in the patients with chronic hepatitis B (P <0. 01) , and 16. 0% in the HBV carriers ( P < 0. 01). There was a significant difference in A1896 mutation between the patients with severe hepatitis B and the patients with chronic hepatitis B (P < 0. 05 ) or the HBV carriers (P<0.05). CONCLUSION: Our observations suggest that the accumulation and persistence of high frequency mutations or complex mutations may be associated with the development and deterioration of HBV infection.

Genomic change in hepatitis B virus associated with development of hepatocellular carcinoma

AIM: To determine the genomic changes in hepatitis B virus(HBV) and evaluate their role in the development of hepatocellular carcinoma(HCC) in patients chronically infected with genotype C HBV.METHODS: Two hundred and forty chronic hepatitis B(CHB) patients were subjected and followed for a median of 105 mo. HCC was diagnosed in accordance with AASLD guidelines. The whole X, S, basal core promoter(BCP), and precore regions of HBV were sequenced using the direct sequencing method.RESULTS: All of the subjects were infected with genotype C HBV. Out of 240 CHB patients, 25(10%) had C1653 T and 33(14%) had T1753 V mutation in X region; 157(65%) had A1762T/G1764 A mutations in BCP region, 50(21%) had G1896 A mutation in precore region and 67(28%) had pre-S deletions. HCC occurred in 6 patients(3%). The prevalence of T1753 V mutation was significantly higher in patients who developed HCC than in those without HCC. The cumulative occurrence rates of HCC were 5% and 19% at 10 and 15 years, respectively, in patients with T1753 V mutant, which were significantly higher than 1% and 1% in those with wild type HBV(P < 0.001).CONCLUSION: The presence of T1753 V mutation in HBV X-gene significantly increases the risk of HCC development in patients chronically infected with genotype C HBV.

Role of hepatitis B virus DNA integration in human hepatocarcinogenesis

Liver cancer ranks sixth in cancer incidence, and is the third leading cause of cancer-related deaths worldwide. Hepatocellular carcinoma (HCC) is the most common type of liver cancer, which arises from hepatocytes and accounts for approximately 70%-85% of cases. Hepatitis B virus (HBV) frequently causes liver inflammation, hepatic damage and subsequent cirrhosis. Integrated viral DNA is found in 85%-90% of HBV-related HCCs. Its presence in tumors from non-cirrhotic livers of children or young adults further supports the role of viral DNA integration in hepatocarcinogenesis. Integration of subgenomic HBV DNA fragments into different locations within the host DNA is a significant feature of chronic HBV infection. Integration has two potential consequences: (1) the host genome becomes altered (&#x0201c;cis&#x0201d; effect); and (2) the HBV genome becomes altered (&#x0201c;trans&#x0201d; effect). The cis effect includes insertional mutagenesis, which can potentially disrupt host gene function or alter host gene regulation. Tumor progression is frequently associated with rearrangement and partial gain or loss of both viral and host sequences. However, the role of integrated HBV DNA in hepatocarcinogenesis remains controversial. Modern technology has provided a new paradigm to further our understanding of disease mechanisms. This review summarizes the role of HBV DNA integration in human carcinogenesis.

Dissecting novel mechanisms of hepatitis B virus related hepatocellular carcinoma using meta-analysis of public data

BACKGROUND Hepatitis B virus(HBV) is a cause of hepatocellular carcinoma(HCC). Interestingly, this process is not necessarily mediated through cirrhosis and may in fact involve oncogenic processes. Prior studies have suggested specific oncogenic gene expression pathways were affected by viral regulatory proteins. Thus, identifying these genes and associated pathways could highlight predictive factors for HCC transformation and has implications in early diagnosis and treatment.AIM To elucidate HBV oncogenesis in HCC and identify potential therapeutic targets.METHODS We employed our Search, Tag, Analyze, Resource platform to conduct a meta-analysis of public data from National Center for Biotechnology Information’s Gene Expression Omnibus. We performed meta-analysis consisting of 155 tumor samples compared against 185 adjacent nontumor samples and analyzed results with ingenuity pathway analysis.RESULTS Our analysis revealed liver X receptors/retinoid X receptor(RXR) activation and farnesoid X receptor/RXR activation as top canonical pathways amongst others. Top upstream regulators identified included the Ras family gene rab-like protein 6(RABL6). The role of RABL6 in oncogenesis is beginning to unfold but its specific role in HBV-related HCC remains undefined. Our causal analysis suggests RABL6 mediates pathogenesis of HBV-related HCC through promotion of genes related to cell division, epigenetic regulation, and Akt signaling. We conducted survival analysis that demonstrated increased mortality with higher RABL6 expression. Additionally, homeobox A10(HOXA10) was a top upstream regulator and was strongly upregulated in our analysis. HOXA10 has recently been demonstrated to contribute to HCC pathogenesis in vitro. Our causal analysis suggests an in vivo role through downregulation of tumor suppressors and other mechanisms.CONCLUSION This meta-analysis describes possible roles of RABL6 and HOXA10 in the pathogenesis of HBV-related HCC. RABL6 and HOXA10 represent potential therapeutic targets and warrant further investigation.

Expression of hepatitis B virus 1.3-fold genome plasmid in an SV40 T-antigen-immortalized mouse hepatic cell line

AIM:To investigate the expression of the hepatitis B virus(HBV)1.3-fold genome plasmid(pHBV1.3)in an immortalized mouse hepatic cell line induced by SV40T-antigen(SV40T)expression.METHODS:Mouse hepatic cells were isolated from mouse liver tissue fragments from 3-5 d old Kunming mice by the direct collagenase digestion method and cultured in vitro.The pRSV-T plasmid was transfected into mouse hepatic cells to establish an SV40LT-immortalized mouse hepatic cell line.The SV40LT-immortalized mouse hepatic cells were identified and transfected with the pHBV1.3 plasmid.The levels of hepatitis B surface antigen(HBsAg)and hepatitis B e antigen(HBeAg)in the supernatant were determined by an electrochemiluminescence immunoassay at 24,48,72 and 96 h after transfection.The expressions of HBsAg and hepatitis B c antigen(HBcAg)in the cells were investigated by indirect immunofluorescence analysis.The presence of HBV DNA replication intermediates in the transfected cells and viral particles in the supernatant of the transfected cell cultures was monitored using the Southern hybridization assay and transmission electronic microscopy,respectively.RESULTS:The pRSV-T plasmid was used to immortalize mouse hepatocytes and an SV40LT-immortalized mouse hepatic cell line was successfully established.SV40LT-immortalized mouse hepatic cells have the same morphology and growth characteristics as primary mouse hepatic cells can be subcultured and produce albumin and cytokeratin-18 in vitro.Immortalized mouse hepatic cells did not show the characteristics of tumor cells,as alpha-fetoprotein levels were comparable(0.58±0.37 vs 0.61±0.31,P=0.37).SV40LTimmortalized mouse hepatic cells were then transfected with the pHBV1.3 plasmid,and it was found that the HBV genome replicated in SV40LT-immortalized mouse hepatic cells.The levels of HBsAg and HBeAg continuously increased in the supernatant after the transfection of pHBV1.3,and began to decrease 72 h after transfection.The expressions of HBsAg and HBcAg were observed in the pHBV1.3-transfected cells.HBV DNA replication intermediates were also observed at72 h after transfection,including relaxed circular DNA,double-stranded DNA and single-stranded DNA.Furthermore,a few 42 nm Dane particles,as well as many22 nm subviral particles with a spherical or filamentous shape,were detected in the supernatant.CONCLUSION:SV40T expression can immortalize mouse hepatic cells,and the pHBV1.3-transfected SV40T-immortalized mouse hepatic cell line can be a new in vitro cell model.

Molecular Characterization of Duck Hepatitis B Virus Isolated from Hubei Brown Ducks

The objective of this study was to characterize the genome structure of duck hepatitis B virus （DHBV） isolated from Hubei brown ducks. The natural carrier rate of DHBV in adult ducks from Hubei area was investigated and the DHBV DNA-positive serum screened out. The complete genome of a DHBV strain was amplified by polymerase chain reaction （PCR） and cloned into T vector and sequenced. The results showed that the carrier rate of DHBV in Hubei brown ducks was 10 % This strain （GenBank accession number DQ276978） had a genome of 3024 nucleotides with three overlapping open reading frames encoding the surface, core and polymerase proteins respectively. Comparison of the strain with 17 DHBV strains registered in GenBank revealed a homology from 89.3 % to 93.5 % at the nucleotide level. The sequences of the structural and functional domains of these proteins were highly conserved. The strain was found to share more signature amino acids in the polymerase genes with the ＂Chinese＂ DHBV strains than those of the ＂Western＂ country strains. This finding was also corroborated by a phylogenetic tree analysis. Therefore, the DQ276978 might belong to a subtype of the Chinese DHBV strains.

Hepatitis B virus pathogenesis: Fresh insights into hepatitis B virus RNA

Hepatitis B virus(HBV) is still a worldwide health concern. While divergent factors are involved in its pathogenesis, it is now clear that HBV RNAs, principally templates for viral proteins and viral DNAs, have diverse biological functions involved in HBV pathogenesis. These functions include viral replication, hepatic fibrosis and hepatocarcinogenesis. Depending on the sequence similarities, HBV RNAs may act as sponges for host mi RNAs and may deregulate mi RNA functions, possibly leading to pathological consequences. Some parts of the HBV RNA molecule may function as viralderived mi RNA, which regulates viral replication. HBV DNA can integrate into the host genomic DNA and produce novel viral-host fusion RNA, which may have pathological functions. To date, elimination of HBVderived covalently closed circular DNA has not been achieved. However, RNA transcription silencing may be an alternative practical approach to treat HBVinduced pathogenesis. A full understanding of HBV RNA transcription and the biological functions of HBV RNA may open a new avenue for the development of novel HBV therapeutics.

Core promoter: A critical region where the hepatitis B virus makes decisions

The core promoter(CP) of the viral genome plays an important role for hepatitis B virus(HBV) replication as it directs initiation of transcription for the synthesis of both the precore and pregenomic(pg) RNAs. The CP consists of the upper regulatory region and the basa core promoter(BCP). The CP overlaps with the 3'-end of the X open reading frames and the 5'-end of the precore region,and contains cis-acting elements that can independently direct transcription of the precore mRNA and pgRNA. Its transcription regulation is under strict control of viral and cellular factors. Even though this regulatory region exhibits high sequence conservation,when variations appear,they may contribute to the persistence of HBV within the host,leading to chronic infection and cirrhosis,and eventually,hepatocellular carcinoma. Among CP sequence variations,those occurring at BCP may dysregulate viral gene expression with emphasis in the hepatitis B e antigen,and contribute to disease progression. In this review these molecular aspects and pathologic topics of core promoter are deeply evaluated.

Hepatitis B virus infection in Latin America:A genomic medicine approach

Hepatitis B virus(HBV)infection is the leading cause of severe chronic liver disease.This article provides a critical view of the importance of genomic medicine for the study of HBV infection and its clinical outcomes in Latin America.Three levels of evolutionary adaptation may correlate with the clinical outcomes of HBV infection.Infections in Latin America are predominantly of genotype H in Mexico and genotype F in Central and South America;these strains have historically circulated among the indigenous population.Both genotypes appear to be linked to a benign course of disease among the native and mestizo Mexicans and native South Americans.In contrast,genotypes F,A and D are common in acute and chronic infections among mestizos with Caucasian ancestry.Hepatocellular carcinoma is rare in Mexicans,but it has been associated with genotype F1b among Argentineans.This observation illustrates the significance of ascertaining the genetic and environmental factors involved in the development of HBV-related liver disease in Latin America,which contrast with those reported in other regions of the world.

Novel therapeutic approaches for hepatitis B virus covalently closed circular DNA

Hepatitis B virus(HBV) infection is a major global health problem. Although current therapies, such as the use of nucleos(t)ide analogs, inhibit HBV replication efficiently, they do not eliminate covalently closed circular DNA(ccc DNA), which persists in hepatocyte nuclei. As HBV ccc DNA is a viral transcription template, novel therapeutic approaches to directly target HBV ccc DNA are necessary to completely eradicate persistent HBV infections. HBV ccc DNA levels in HBV-infected human liver cells are extremely low; thus, more reliable and simple measurement methods are needed to correctly monitor their levels during therapeutic treatment. Although reverse transcription-polymerase chain reaction or Southern blot procedures are currently used in research studies, these methods are not completely reliable and are also time-consuming and labor-intensive. Genome editing technologies, such as zinc finger nucleases, transcription activator-like effector nucleases, and the clustered regularly interspaced short palindromic repeats/Cas9(CRISPR/Cas9) system, which are designed to target specific DNA sequences, represent highly promising potential therapeutic tools. In particular, the CRISPR/Cas9 system is an easily customizable sequencespecific nuclease with high flexibility and may be the most feasible approach to target HBV ccc DNA. Further research to develop easier, safer, and more effective protocols should be pursued.

Mutation analyses of integrated HBV genome in hepatitis B patients

Little has been learnt in the last 30 years about detection of HBV genome as well as its mutation analysis between hepatitis B fathers （HBF） and their children. In this study, we used nest polymerase chain reaction （PCR）, fluorescence in situ hybridization （FISH）, and DNA sequencing analysis, to examine the integrated HBV genome in paraffin-embedded testis tissues, which were taken as samples from HBE and in peripheral blood mononuclear cells （PBMC） from 74 cases of HBFs and their children who were born after their fathers＇ HBV infection （caHBF）. We found that HBV DNA existed in testis tissues, mainly in the basilar parts of the seminiferous tubules, and also in PBMC of HBE It was also documented that there were point mutations of poly-loci, insertions and deletions of nucleotides in integrated HBV genomes, and the types of gene mutations in the HBFs were similar to those in caHBE This study addresses the major types of gene mutations in integrated HBV genome in human patients and also presents reliable evidence of possible genetic transmission of hepatitis B.

HLA class Ⅱ associated with outcomes of hepatitis B and C infections

Several factors influence the clinical course of hepatitis B virus(HBV)and hepatitis C virus(HCV)infection.The human leukocyte antigen(HLA)system,the major histocompatibility complex(MHC)in humans,has been considered one of the most important host factors with respect to outcomes.To date,conventional genotyping studies have shown that HLA classⅡloci are mainly associated with spontaneous clearance of HBV and HCV.However,the specific HLA locus associated with the outcomes of hepatitis virus infection remains unclear.A recent genome-wide association study(GWAS)using a comprehensive approach for human genotyping demonstrated single nucleotide polymorphisms(SNPs)associated with the outcomes of hepatitis virus infection.Examination of large numbers of cohorts revealed that several SNPs in both HLA-DPA1 and HLADPB1 loci are associated with persistent HBV infection in Asian populations.To date,however,few studies have focused on HLA-DP because polymorphisms of HLA-DP haplotype do not vary greatly as compared with other loci of HLA.There are not enough studies to reveal the function of HLA-DP.GWAS additionally detected candidate SNPs within HLA loci associated with chronic HBV or HCV hepatitis,hepatic fibrosis,and the development of hepatocellular carcinoma.The results of one cohort were not always consistent with those of other cohorts.To solve several controversial issues,it is necessary to validate reported SNPs on HLA loci in global populations and to elucidate the HLA-allele-regulated molecular response to hepatitis virus infection.

How did hepatitis B virus effect the host genome in the last decade?

The principal reason of chronic liver disease,cirrhosis and hepatocellular carcinoma is chronic viral hepatitis all over the world.Hepatitis B virus(HBV)has some mutagenic effects on the host genome.HBV may be exhibiting these mutagenic effects through integrating into the host genome,through its viral proteins or through some epigenetic mechanisms related with HBV proteins.This review aims to summarize the molecular mechanisms used by HBV for effecting host genome determined in the last decade.The focus will be on the effects of integration,HBV proteins,especially HBV X protein and epigenetic mechanisms on the host genome.These interactions between HBV and the host genome also forms the underlying mechanisms of the evolution of hepatocellular carcinoma.

Induction of endoplasmic reticulum-derived oxidative stress by an occult infection related S surface antigen variant

AIM: To investigate the mechanism of endoplasmic reticulum(ER) stress induction by an occult infection related hepatitis B virus S surface antigen(HBsAg)variant.METHODS: We used an HBsAg variant with lower secretion capacity, which was a KD variant from a Korean subject who was occultly infected with the genotype C. We compared the expression profiles of ER stress-related proteins between HuH-7 cells transfected with HBsAg plasmids of a wild-type and a KD variant using Western blot.RESULTS: Confocal microscopy indicated that the KD variant had higher levels of co-localization with ER than the wild-type HBsAg. The KD variant upregulated ER stress-related proteins and induced reactive oxygen species(ROS) compared to the wildtype via an increase in calcium. The KD variant also down-regulated anti-oxidant proteins(HO-1, catalase and SOD) compared to the wild-type, which indicates positive amplification loops of the ER-ROS axis. The KD variant also induced apoptotic cell death via the upregulation of caspase proteins(caspase 6, 9 and 12).Furthermore, the KD variant induced a higher level of nitric oxide than wild-type HBsAg via the up-regulation of the iNOS protein.CONCLUSION: Our data indicate that occult infection related HBsAg variants can lead to ER-derived oxidative stress and liver cell death in HuH-7 cells.

乙型肝炎病毒中国流行株B、C、D/C及A基因型的全基因克隆与序列分析

目的:扩增克隆乙型肝炎病毒(HBV)B,C,D/C及A基因型的全基因组,构建不同基因型的全基因序列克隆.方法:从中国慢性乙型肝炎患者血清提取DNA以L-PCR技术对3.2kb的HBVDNA进行扩增,纯化后克隆到TA载体.对于HBV不同基因型的全基因序列利用Simplot、DNAStar(ClustalW方法的MegAlign和Phylogenetictree)等生物软件进行分析.结果:克隆出我国主要存在的几种HBVDNA全基因序列:B、C、D/C和A基因型,包括:adr、adw、ayw血清型.B基因型(adw血清型)全基因序列长度为3215bp,C基因型(adrq+血清型)为3215bp,D/C基因型(ayw2血清型)为3215bp,A基因型(adw血清型)为3182bp,均递交GenBank.在H3样品中的4个全基因克隆中存在一个同时含有2853-2885nt缺失突变和核心区的1762A-T、1764G-A双位点突变的变异株,表明同一个体中同时存在突变株和野生株,可能是耐抗病毒药物的分子基础.结论:本研究克隆了我国有报道存在的主要基因型、血清型的HBV全基因序列,为全面了解我国HBV基因型和血清型提供了序列资料.

血清乙型肝炎病毒DNA水平对HBV全基因组克隆效率的影响

目的:通过比较血清HBV DNA水平对一片段PCR法和两片段PCR法这两种不同方法的HBV全基因组克隆效率的影响,选择出合适的HBV全基因组克隆技术,供后续的HBV的基础和临床研究。方法:采集了慢性乙型肝炎(CHB)患者85份血清,分别用本研究建立的一片段PCR法及两片段PCR法扩增HBV全基因组,经双酶切鉴定后将PCR产物克隆入载体,进行HBV全基因组序列测定。同时用实时荧光定量PCR法检测上述85份血清的HBV DNA滴度。结果:本研究建立的一片段PCR法扩增成功需要的血清HBV DNA浓度高于两片段PCR法,两种方法扩增的效率比较为:一片段PCR法扩增的阳性率低于两片段PCR法(P<0.01)。一片段PCR法的保真性和灵敏度分析发现:保真性:核苷酸的人为突变率为1.13bp/kb;灵敏度:为102个初始模板。浓度大于103的重组质粒DNA80%可以成功扩增,浓度低于该值的扩增效率比较低。结论:血清HBV DNA水平对两种扩增方法的阳性率有一定影响,滴度高低是选择合适PCR扩增方法的依据。HBV DNA滴度大于106copies/L的样本,可选用一片段PCR法的全基因组扩增、克隆技术,而对HBV DNA滴度小于106copies/L样本,则可选用两片段PCR法的全基因组扩增、克隆技术。本研究建立的一片段PCR法扩增HBV全基因组克隆的技术是一种值得推荐的好方法,但还需进一步优化。

2.2kb乙型肝炎病毒剪接特异性蛋白对Huh7细胞基因表达的影响

目的研究单剪接及双剪接型2.2 kb乙型肝炎病毒基因编码剪接特异性蛋白(分别为TPss及TPds)对Huh7细胞基因表达的影响,探讨其可能的致病机制。方法PCR扩增TPss及TPds编码序列并克隆入pcDNA3.1/HisC。采用FuGENE6将重组表达载体及相应空载体分别瞬时转染Huh7细胞,Trizol抽提细胞总蛋白与总RNA。以Westernblot检测目的蛋白的表达,通过Affymetrix Genechip U133 plus 2.0人类基因表达谱芯片检测Huh7肝细胞基因转录的变化并以半定量RT-PCR进一步验证。结果成功构建重组真核表达载体pcDNA3.1/HisC-TPss及pcDNA3.1/HisC-TPds,在Huh7细胞中能分别表达TPss(单剪接)及TPds(双剪接)蛋白。TPss蛋白导致Huh7细胞DGKβ(diacyl-glycerol kinase beta)等4个基因转录上调,ZNF652(zinc finger protein 652)等5个基因转录下降;TPds蛋白导致细胞MTSS1(Metastasis suppressor 1)等3个基因转录上调,WARS2基因(Tryptophanyl tRNA synthetase 2)转录下降。结论2.2 kb乙型肝炎病毒基因组剪接体编码剪接特异性蛋白可能影响肝细胞骨架的重塑、细胞内物质代谢等方面,与肝细胞的增生、迁移及代谢异常密切相关。