@article{mbs:/content/journal/jgv/10.1099/0022-1317-69-5-975, author = "Shelbourn, S. L. and Day, P. R. and Buck, K. W.", title = "Relationships and Functions of Virus Double-stranded RNA in a P4 Killer Strain of Ustilago maydis", journal= "Journal of General Virology", year = "1988", volume = "69", number = "5", pages = "975-982", doi = "https://doi.org/10.1099/0022-1317-69-5-975", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-69-5-975", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", keywords = "Ustilago maydis", keywords = "killer proteins", keywords = "double-stranded RNA", keywords = "capsid polypeptide", abstract = "Summary Double-stranded RNA (dsRNA) from virus particles isolated from a P4 killer strain (isolate 77) of Ustilago maydis, which secretes a protein toxin of apparent M r approx. 10000 (10K) was resolved by PAGE into eight segments with sizes (kbp) 6·7 (H1), 4·5 (H2), 3·2 (H3a), 3·1 (H3b), 2·6 (H4), 0·98 (M2-4), 0·92 (M3-4) and 0·36 (L1). A subculture, designated 77-3A, was found to have lost the H2 and M3-4 segments, but still produced virus particles and protein toxin. Northern hybridization showed that dsRNA segments M2-4 and L1 are related but no homology was detected between H1, H3a, H3b and H4, or between any of these H segments and M2-4 or L1. When individual denatured dsRNA segments were translated in vitro in a reticulocyte lysate system H1, H3a, H3b and H4 each gave rise to polypeptides in the M r range 100K to 128K. Polypeptides of apparent M r 108K and 128K, encoded by H3b, and 100K, encoded by H4, were immunoprecipitated by antiserum to purified virus particles from subculture 77-3A. In vitro translation of denatured M2-4 gave rise to polypeptides of apparent M r 26K and 13K which were immunoprecipitated by antiserum to the secreted protein toxin. No in vitro translation product was detected from denatured L1.", }