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Resting complexes of the persistent yeast 20 S RNA N arnavirus consist solely of the 20 S RNA viral genome and its RNA polymerase p91
Author(s) -
Vega Lorena,
Sevillano Laura,
Esteban Rosa,
Fujimura Tsutomu
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12724
Subject(s) - rna , biology , ribonucleoprotein , rna polymerase , rna polymerase i , rna dependent rna polymerase , rna silencing , non coding rna , signal recognition particle rna , polymerase , small nuclear rna , microbiology and biotechnology , genetics , gene , rna interference
Summary The positive strand 20 S RNA narnavirus persistently infects S accharomyces cerevisiae . The 20 S RNA genome has a single gene that encodes the RNA ‐dependent RNA polymerase (p91). 20 S RNA forms ribonucleoprotein resting complexes ( RNPs ) with p91 and resides in the cytoplasm. Here we found no host proteins stoichiometrically associated with the RNP by pull‐down experiments. Furthermore, 20 S RNA , when expressed from a vector in E scherichia coli , formed RNPs with p91 in the absence of yeast proteins. This interaction required the 3′ cis signal for complex formation. Moreover, when 23 S RNA , the genome of another narnavirus, was expressed in E . coli , it also formed RNPs with its RNA polymerase p104. Finally, when both RNA s were expressed in the same E . coli cell, they formed RNPs only with their cognate RNA polymerases. These results altogether indicate that narnaviruses RNPs consist of only the viral genomes and their cognate RNA polymerases. Because the copy number of the RNPs can be induced almost equivalent to those of rRNAs in some yeast strains, the absence of host proteins may alleviate the burden on the host by not sequestering proteins into the RNPs . It may also contribute to the persistent infection of narnaviruses by decreasing their visibility.