An arginine-to-proline mutation in a domain with undefined functions within the helicase protein (Nsp13) is lethal to the coronavirus infectious bronchitis virus in cultured cells.

摘要: Genetic manipulation of the RNA genomes by reverse genetics is a powerful tool to study molecular biology and pathogenesis viruses. During construction an infectious clone from Vero cell-adapted coronavirus bronchitis virus (IBV), we found that G-C point mutation at nucleotide position 15526, causing Arg-to-Pro amino acid 132 helicase protein, lethal infectivity IBV on cells. When in vitro-synthesized full-length transcripts containing this were introduced into cells, no was rescued. Upon correction mutation, recovered. Further characterization G15526C demonstrated may block transcription subgenomic RNAs. Substitution Arg132 residue positively charged Lys affected neither nor growth properties rescued virus. However, Leu, conserved other coronaviruses same position, reduced recovery rate transcripts. The recovered mutant showed much smaller-sized plaques. On contrary, G-A mutations positions 4330 9230, respectively, Glu-Gln Gly-Glu or near catalytic centers papain-like (Nsp3) 3C-like (Nsp5) proteinases, did not show detectable detrimental effect rescue viruses