Expression and characterization of the hepatitis E virus ORF3 protein in the methylotrophic yeast, Pichia pastoris

Sunil K. Lal, P. Tulasiram, Shahid Jameel

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22 Citations (Scopus)


We have used the methylotrophic yeast, Pichia pastoris, to express the open reading frame 3 (ORF3) of the hepatitis E virus (HEV). The ORF3 gene codes for a 123-amino-acid protein that contains highly immunodominant epitopes and is a potentially useful diagnostic and immunoprophylactic antigen. The expressed protein showed positive on immunoblots probed against antibodies raised in rabbit and infected human patient sera. In order to optimize the ORF3 protein expression, we have examined the regulated expression of this protein and characterized it. Unlike its expression in E. coli, the ORF3 protein was present in both the soluble and insoluble fractions of the cell lysate. The expressed protein is not glycosylated and does not undergo any major processing in the host strain.

Original languageEnglish
Pages (from-to)63-67
Number of pages5
Issue number1
Publication statusPublished - 29 Apr 1997
Externally publishedYes


  • Alcohol oxidase promoter
  • Expression plasmid
  • Glycosylation pattern
  • Heterologous gene expression
  • Integrative transformation
  • Methanol utilization pathway
  • Open reading frame

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