The rtL229 substitutions in the reverse transcriptase region of hepatitis B virus (HBV) polymerase are potentially associated with lamivudine resistance as a compensatory mutation.

Background: It remains unclear whether hepatitis B virus (HBV) reverse-transcriptase (RT) rtL229 substitutions influence HBV drug resistance.

Objective: The study was to investigate the association of HBV rtL229 substitutions with viral resistance to lamivudine (LAM).

Study Design: Entire HBV RT genes were amplified by nested PCR and sequenced from sera of 6000 nucleos(t)ide analog-experienced patients with chronic HBV infection.

Characterization of hepatitis B virus genotypes/subgenotypes in 1,301 patients with chronic hepatitis B in North China.

Background: There is still a paucity of data on hepatitis B virus (HBV) subgenotype prevalence in North China based on sequencing of large-size samples. In addition, whether HBV genotypes impact drug-resistance-associated and HBV e antigen (HBeAg)-loss-associated mutations in patients with chronic hepatitis B (CHB) is still under investigation. This study aimed to disclose clinical prevalence of HBV genotypes/subgenotypes in North China and the clinical implications of HBV genotype classification in respect to HBeAg loss and drug-resistant occurrence.

Identification of genes upregulated by recombinant interferon-alpha in HepG2 cells by suppressive subtractive hybridization analysis.

Background: Interferon-alpha (IFN-alpha) is an important cytokine with multiple functions, but the target genes transactivated by IFN-alpha remain largely unknown. A study of such genes will help to understand the mechanism of function of IFN-alpha. To isolate the gene transcripts specifically upregulated by IFN-alpha in HepG2 cells, we conducted suppressive subtractive hybridization (SSH) analysis.

[Screening and identification of proteins interacting with HCV NS4A via yeast double hybridization in leukocytes and gene cloning of the interacting protein].

Objective: To screen proteins interacting with HCV NS4A protein in leukocytes by yeast-double hybridization.

Methods: The bait plasmid pGBKT7-NS4A was transformed into yeast AH109 was transformed, and the expressing of the fusion protein was identified by SDS-page. The transformed yeast was mated with yeast Y187 containing leukocytes cDNA library plasmid in 2xYPDA medium.

[Transcriptional inhibitory effect of hepatitis B virus X protein on the expression of p53 tumor suppression gene].

Background: To investigate the transcriptional inhibitory role of hepatitis B virus X protein on the expression of p53 tumor suppression gene.

Methods: The promoter sequence of the p53 tumor suppression gene was identified and amplified by bioinformatics and polymerase chain reaction (PCR). The recombinant reporter gene expression vector pCAT3-p53p was constructed and transfected into the hepatoblastoma cell line HepG2 and cotransfected with pcDNA3.

[Study of the down-regulating effect of hepatitis C virus NS5A protein on NACA promoter].

Objective: To investigate the effect of hepatitis C virus (HCV) non-structure protein NS5A on the activity of calcium-regulating protein alpha subunit of nascent polypeptide-associated complex (NACA) promoter.

Methods: HepG2 cell plasmid pCAT3-NACA, containing NACA promoter, was transfected alone or cotransfected with pcDNA3.1(-)-NS5A, and chloramphenicol acetyl transferase (CAT) enzyme activity was assayed by enzyme-linked immunoassay (ELISA).

[Screening of binding proteins to interferon-alpha promoter DNA by phage display technique].

Objective: To investigate the interferon alpha regulation mechanisms by screening binding proteins of interferon alpha promoter by phage display.

Methods: PCR product of interferon-alpha promoter was incubated with a phage display cDNA library that expressed a library of human liver proteins on the surface of bacteriophage T7. Unbound phages were washed off and the phages bound to the interferon alpha promoter were amplified.