Studies of the genomic RNA of leukosis viruses: implications for RNA dimerization.

Abstract:

Retroviral particles contain two positive-strand genomic RNAs linked together by noncovalent bonds that can be dissociated under mild conditions. We studied genomic RNAs of wild-type and mutant avian leukosis viruses (ALVs) in an attempt to (i) better understand the site(s) of RNA dimerization, (ii) examine whether the primer binding site (PBS) and tRNA primer are involved in dimerization, and (iii) determine the structure of genomic RNA in protease-deficient (PR(-)) mutants. We showed that extensively nicked wild-type ALV genomic RNAs melt cooperatively. This implies a complex secondary and/or tertiary structure for these RNAs that extends well beyond the 5' dimerization site. To investigate the role of the PBS-tRNA complex in dimerization, we analyzed genomic RNAs from mutant viruses in which the tRNA(Trp) PBS had been replaced with sequences homologous to the 3' end of six other chicken tRNAs. We found the genomic RNAs of these viruses are dimers that dissociate at the same temperature as wild-type viral RNA, which suggests that the identity of the PBS and the tRNA primer do not affect dimer stability. We studied two ALV PR(-) mutants: one containing a large (>1.9-kb) inversion spanning the 3' end of gag and much of pol, rendering it deficient in PR, reverse transcriptase, and integrase, and another with a point mutation in PR. In both of these mutant viruses, the genomic RNA appears to be either primarily or exclusively monomeric. These data suggest that ALV can package its RNA as monomers that subsequently dimerize.

Polymerases:

Topics:

Status:

new topics/pols set partial results complete validated

Results:

No results available for this paper.

Entry validated by:

Log in to edit reference All References

Using Polbase tables:

Sorting:

Tables may be sorted by clicking on any of the column titles. A second click reverses the sort order. <Ctrl> + click on the column titles to sort by more than one column (e.g. family then name).

Filtering:

It is also possible to filter the table by typing into the search box above the table. This will instantly hide lines from the table that do not contain your search text.