Coronaviral hypothetical and structural proteins were found in the intestinal surface enterocytes and pneumocytes of severe acute respiratory syndrome (SARS)

The putative protein 6 of the severe acute respiratory syndrome-associated coronavirus: expression and functional characterization

The SARS‐CoV open reading frame 6 (ORF6) is transcribed into mRNA6 and encodes a putative 7.5 kDa accessory protein, SARS 6, with unknown function. In this study, we have confirmed the SARS 6 protein expression in lung and intestine tissues of the SARS patients and in SARS‐CoV infected Vero E6 cells by immunohistochemistry. Further studies by immunoblot and confocal microscopy analyses revealed the expression and the endoplasmic reticulum (ER) localization of the recombinant SARS 6 protein in mammalian cells. Expression of SARS 6 protein in mammalian cells elicits biological activity of stimulating cellular DNA synthesis.