Expression data from the hepatitis E virus capsid protein

The hepatitis E virus (HEV), a non enveloped RNA virus, causes viral hepatitis. The viral open reading frame 2 (ORF2) protein represents the capsid protein of HEV which is known to cause endoplasmic reticulum stress in ORF2 expressing cells. The initiation of endoplasmic reticulum stress induced apoptosis mainly involves the transcriptional activation of pro-apoptotic gene CHOP which will further trigger the major apoptotic pathways. However, the activation of CHOP by ORF2 protein in this study does not induce apoptotic markers such as Bax translocation to mitochondria. We have used the Affymetrix microarray platform to screen the pro-apoptotic effects induced by the expression of ORF2 protein in human hepatic cell lines (Huh7). The Huh7 cells were transduced either with recombinant adenovirus encoding the HEV ORF2 (Ad-ORF2) or an adenovirus encoding the green fluorescent protein (Ad-GFP). The array results consistently showed an ORF2 specific induction of mRNA corresponding to the chaperones Hsp72, Hsp70B and co-chaperone Hsp40. These studies provide further mechanisms of the ER stress mediated pro apoptotic effects caused by the ORF2 protein and its potential role for the activation of anti-apoptotic activity of the host cell.

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John L, Thomas S, Herchenröder O, Pützer BM, Schaefer S