Circular single-stranded RNA replicon in Saccharomyces cerevisiae.

AUTOR(ES)

Matsumoto, Y

RESUMO

Circular RNA replicons have been reported in plants and, in one case, in animal cells. We describe such an element in yeast. In certain yeast strains, a 20S RNA species appears on transfer of cells to acetate medium. This phenotype shows cytoplasmic (non-Mendelian) inheritance and the 20S RNA is associated with 23-kDa protein subunits as a 32S particle. We demonstrate that yeast 20S RNA is an independent replicon with no homology to host genomic, mitochondrial, or 2-microns plasmid DNA or to the L-A, L-BC, or M1 double-stranded RNA viruses of yeast. The circularity of the 20S RNA is shown by the apparent absence of 3' and 5' ends, by two-dimensional gel electrophoresis, and by electron microscopy. Replication of yeast 20S RNA proceeds through an RNA-RNA pathway, and a 10,000-fold amplification occurs on shift to acetate medium. The copy number of 20S RNA is also reduced severalfold by the SKI gene products, a host antiviral system that also lowers the copy numbers of yeast double-stranded RNA viruses. Yeast 20S RNA and the hepatitis delta virus show some similarities.

Documentos Relacionados

• Homologous recombination between single-stranded DNA and chromosomal genes in Saccharomyces cerevisiae.
• Replication of single-stranded DNA templates by primase-polymerase complexes of the yeast, Saccharomyces cerevisiae.
• Different base per unit length ratios exist in single-stranded RNA and single-stranded DNA.
• Double-Length, Circular, Single-Stranded DNA from Filamentous Phage
• Poliovirus single-stranded RNA and double-stranded RNA: differential infectivity in enucleate cells.