Structure and nuclear localization signal of the SKI3 antiviral protein of Saccharomyces cerevisiae.
The yeast chromosomal genes SKI2, SKI3, SKI4, SKI6, SKI7 and SKI8 repress the replication of double-stranded RNA viruses, protecting the host from the otherwise lethal effects of the virus. We cloned and sequenced the SKI3 gene and found that it encodes a 163 kDa protein including a typical nuclear localization signal. Cell fractionation experiments show that the SKI3 gene product is indeed tightly associated with nuclei and that the putative nuclear localization sequence directs beta-galactosidase into the nucleus. However, fusion of a part of the SKI3 protein lacking this signal with beta-galactosidase also directs beta-galactosidase into the nucleus, suggesting the presence of a second nuclear localization signal. The SKI3 gene is only essential in the presence of an M double-stranded RNA virus.
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Section on Genetics of Simple Eukaryotes, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
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D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D012328:RNA Viruses / Q000502:physiology*; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D013172:Spores, Fungal; D014779:Virus Replication
D004271:DNA, Fungal; D005656:Fungal Proteins; D009687:Nuclear Proteins