Genes trans-regulated by nonstructural protein 5A of hepatitis C virus with microarray assay

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Cloning and identification of NS5ATP2 gene and its spliced variant transactivated by hepatitis C virus non-structural protein 5A

AIM: To clone and identify a new gene NS5ATP2 and its spliced variant transactivated by hepatitis C virus non-structural protein 5A.

METHODS: On the base of subtractive cDNA library of genes transactivated by NS5A protein of hepatitis C virus, the coding sequence of new gene and its spliced variant were obtained by bioinformatics methods. Polymerase chain reaction (PCR) was conducted to amplify NS5ATP2 gene.

RESULTS: The coding sequence of new gene and its spliced variant were cloned and Identification successfully.

CONCLUSION: A novel gene has been recognized as the new target transactivated by HCV NS5A protein. These results bring some new clues for studying the biological functions of the new gene and pathogenesis of the viral proteins.

Up-regulating effect of hepatitis C virus NS5A protein on NS3TP6 gene promoter

AIM: To investigate the regulatory effects of non-structural protein 5A of hepatitis C virus (HCV NS) protein on NS3TP6 gene promoter.

METHODS: The sequence of NS3TP6 gene promoter was identified in GenBank by bioinformatics and amplified from HepG2 genome by polymerase chain reaction (PCR), which was cloned into pCAT3 reporter vector. The HepG2 cell line was transfected by pCAT3-NS3TP6-p, and co-tranfected by pCAT3-NS3TP6-p and pcDNA3.1(-)-NS5A, respectively. The chloramphenicol acetyltransferase (CAT) activity was detected by an enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS: The recombinant vector of reporter gene expressive vector pCAT3-NS3TP6-p was approved correctly by restriction enzyme digestion and sequencing analysis. In the transfection experiment of HepG2, pCAT3-NS3TP6-p had higher activity of CAT expression than that of pCAT3-basic demonstrated by an ELISA kit. The expression level of CAT in co-transfection of pCAT3-NS3TP6-p and pcDNA3.1(-)-NS5A was 1.87 times as higher as that of pCAT3- NS3TP6-p plasmid alone.

CONCLUSION: Cell transfection and ELISA technology are successfully used to prove the results from microarray of HCV NS5A, which brings some new clues for studying the trans-regulated and immune regulation mechanism of NS5A.

Effects of HCBP6 protein on transact-ivating function of HCV core protein

AIM: To study the inhibitory effects of HCBP6 on the transactivating effect of HCV core protein.

METHODS: The recombinant vectors expressive HCV core protein and HCBP6 protein were constructed, respectively, by routine molecular techniques. The hepatoblastoma cell line HepG2 were co-transfected. The chloramphenicol transferase (CAT) expressive levels under the SV40 early promoter were determined by an enzyme-linked immuno-sorbent assay (ELISA) kit.

RESULTS: The recombinant vectors of pcDNA3.1(-)-HCBP6 and pcDNA3.1(-)-core were constructed, and demonstrated correctly by restriction enzyme digestion and sequencing analysis. The hepatoblastoma cell line HepG2 was transfected with the vector alone or combined, respectively. The expression level of CAT indicated that the inhibitory rate was 40.4%-62.3%.

CONCLUSION: The expression of HCBP6 has inhibitory effects on the transacting activity of HCV core protein.

Screening and identification of genes transactivated by human augmenter of liver regeneration by microarray assay

AIM: Augmenter of liver regeneration (ALR) is a protein that plays a role in liver regeneration. In order to clarify the effect of the expression of ALR on profile of the hepatocytic gene expression, we analyzed difference between the HepG2 cells transfected with ALR and controls by using gene chip technology.

METHODS: Total RNA was extracted from HepG2 cells,and RT-PCR was performed to amplify the coding region of ALR. The expression of ALR in the transfected HepG2 cells was confirmed by Western blot. Total mRNA was isolated from the transfected HepG2 cells with pcDNA3.1(-) and pcDNA3-ALR, respectively. cDNA was prepared by reverse transcription. Microarray assay was conducted for screening of up-and down-regulated genes in both HepG2 cells.

RESULTS: The expressive vector of pcDNA3(-)-ALR was constructed and confirmed by restriction enzyme digestion and DNA sequencing. The expression of ALR was confirmed by Western blot. After screening with cDNA microarray, we found 2 genes were up-regulated, and 24 genes including TNFRSF1A-associated via death domain, tissue inhibitor of metalloproteinase 1, epididymal androgen-related protein, down-regulated.

CONCLUSION: ALR is a cell growth factor, which has some influences on gene expression profile of hepatocytes; Microarray technology is a method to analyze gene expression spectra of trans-regulation of a protein and conducive to understand the regulative effect of ALR on hepatocytes and other biological function.

Screening and identification of genes transactivated by NS5A-TP4 protein by cDNA microarray assay

AIM: To study the molecular mechanism of NS5A-TP4 in the up- and down-regulated genes of hepatocyte by cDNA microarray assay.

METHODS: HepG2 cells were transfected by recombined expression plasmid pcDNA3.1(-)-NS5A-TP4. Total RNA was isolated from the transfected HepG2 cells with pcDNA3.1(-) and pcDNA3.1(-)-NS5A-TP4, respectively. cDNA was prepared by reverse transcription. cDNA microarray was conducted for screening of up- and down-regulated genes of both HepG2 cells.

RESULTS: After screening with cDNA microarray, we found that 12 genes were up-regulated, and 6 genes down-regulated. Some of them were involved in cell signal transduction, cell proliferation, and carcinogenesis.

CONCLUSION: cDNA microarray is an important choice for the analysis of target genes of NS5ATP4 transactivation. The obtained sequences bring some new clues for studying the biological functions of NS5ATP4 and infection mechanism of HCV.

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Identification and characterization of retinol dehydrogenase 11 as a hepatitis C virus core protein-binding protein by yeast-two hybrid technique

AIM: To screen the hepatocyte protein interacting with HCV core protein.

METHODS: By using HCV core protein as a bait, yeast-two hybrid system 3 was employed for screening and identification of HCV core protein-binding proteins from a hepatocyte cDNA library expressed in yeast cells. The protein-protein interaction was confirmed by back-cross experiment, and the inserts of the expressive vectors were sequenced and analyzed by bioinformatics methods.

RESULTS: Among them we identified retinol dehydrogenase 11(RDH11/androgen- regulated short-chain dehydrogenase/reductase 1 (ARSDR1) as a HCV core protein-interacting protein. This is the first time, to the best of our knowledge, to know the fact that there are interactions of HCV core protein-retinol dehydrogenase 11.

CONCLUSION: The identification of retinol dehydrogenase 11 as the HCV core protein binding partner paves a new way for further understanding of the pathogenesis of HCV infection.

Identification and sequence analysis of mouse homologous gene coding for hepatitis C virus non-structural protein 5A-binding protein 37

AIM: To clone murine homologous gene to human NS5ABP37 gene, and to elucidate its biological functions and the possible effects in the pathogenesis of hepatitis C virus (HCV) infection.

METHODS: Yeast-two hybrid system was employed to screen the human liver cDNA library by using non-structural protein 5A (NS5A) of hepatitis C virus (HCV) as the bait. According to the homologous role between the species, a murine NS5ABP37 homologous to human NS5ABP37 was deduced by bioinformatics methods. The primary sequence of murine NS5ABP37 was searched for conserved domains by online tools of GeneBank.

RESULTS: Human NS5ABP37 was screened and cloned from human liver cDNA library by yeast-two hybrid system 3. The murine NS5ABP37 was deduced by bioinformatics methods. The open reading frame (ORF) of murine NS5ABP37 consisted of 1 488 nt encoding a protein of 495 amino acids. Calculated molecular weight was 54 583.67 dalton and predicted pI was 4.70. From the homologous protein search, murine NS5ABP37 was demonstrated homologous to leukocyte antigen related (LAR) protein precursor. The sequence of murine NS5ABP37 was deposited into GenBank, and the accession number was AY234860.

CONCLUSION: Successful identification and cloning of murine NS5ABP37, which is homologous to LAR protein precursor, paves a way for elucidating the biological function of murine NS5ABP37 and pathogenesis of hepatitis C virus infection.

Cloning of the gene of preS1 promoter of hepatitis B virus specific DNA-binding protein 1

AIM: To identify the protein which has unknown function binding with the preS1 promoter of hepatitis B virus, and to clone its coding sequence.

METHODS: Yeast one-hybrid system was employed to screen a human liver cDNA library using 3 copies of SP I core sequence as a bait, and one unknown gene was obtained. The coding sequence of the preS1 promoter of hepatitis B virus specific DNA-binding protein 1 (SBP I) was cloned by bioinformatics methods.

RESULTS: The coding sequence of SBP1 was cloned successfully.

CONCLUSION: SBP1 has a complete open reading frame, and biological functions by binding with SP I. The sequence similarity results indicate that the human SBP1 is a new member of transcription factor C/EBP.

Screening of the genes of HCV core interacting proteins from human leucocyte cDNA library by yeast two-hybrid system

AIM: To investigate the binding protein of hepatitis C virus core protein (HCVcore).

METHODS: The HCVcore gene was amplified by polymerase chain reaction (PCR) and HCVcore bait plasmid was constructed by using yeast-two hybrid system 3, then transformed into yeast AH109. The transformed yeast mated with yeast Y187 containing leucocyte cDNA library plasmid in 2×YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-α-gal for selecting two times and screening. After extracting and sequencing of plasmid from blue colonies, we underwent analysis by bioinformatics.

RESULTS: Six colonies were sequenced, among which,two colonies were golgi complex associated protein 1 (GOCAP1), one colony was Ran binding protein M (RanBPM), one colony was pellino homolog 2 (PELI2), and two colonies were KIAA1949 protein (KIAA1949).

CONCLUSION: Genes of HCV core interacting proteins in leucocyte are successfully cloned and the results bring some new clues for studying the biological functions of HCVcore and associated proteins.