Expression and Processing of Nonstructural Proteins of the Human Astroviruses
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The human astroviruses (HAst) are increasingly recognized as an important cause of gastroenteritis. These viruses contain a 6.8-kb positive-sense, single-stranded RNA molecule that is infectious when transfected into permissive cells. The HAst gene 1 is composed of two open reading frames (ORFs 1a and 1b) connected by a ribosomal frameshift. Gene 1 is predicted to encode two nonstructural polyproteins (pp1a and pp1ab), and analysis of the HAs gene 1 sequence has resulted in predictions of a serine proteinase within the ORF1a polyprotein. However, none of the gene 1 proteins have been identified. To examine the expression and processing of the HAst2 gene 1 polyprotein, we have translated pp1a and pp1ab in vitro. These ongoing studies will provide the foundation for correlating gene 1 expression in vitro with proteins expressed in virus-infected cells.
KeywordsNonstructural Protein Permissive Cell Ribosomal Frameshift Antigenic Domain eDNA Clone
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