Electron microscopy of double-stranded nucleic acids found in tissue infected with the satellite of tobacco ringspot virus.
Electron microscopic studies of the ds RNAs purified from plants infected with the satellite (S) of tobacco ringspot virus (TobRSV) revealed that approximately 91% of the population is linear, varying in length between 40 and 3000 nm. Six percent of the population appeared as relaxed circles, and the balance appeared as "racket"-like structures. Electrophoretic analysis of these preparations detected at least 12 components higher in molecular weight than the expected 230,000-dalton RF. Denaturation of the same sample released ss RNA that coelectrophoresed with STobRSV RNA from virions. The linear ds molecules, although extremely variable in length, have some preferential distribution around 130 nm, not around 68 nm, the length of ss STobRSV RNA; the circles also varied, but their lengths fell into four distinct peaks: the shortest was 130 nm, and the increment of each longer circle was also about 130 nm. The circular portion of the "racket"-like structure was a uniform 130 nm, with a varied linear portion. However, the most frequent linear dimension was also 130 nm. Denatured ds RNA varied in length, and most molecules fell in between 50 and 185 nm. Relaxed circles and "racket"-like structures were also present, but much less frequently than in the undenatured preparation. T1 RNase degradation of ds StobRSV RNA made the linear population more uniform in length (between 60 and 130 nm), most preferentially around 130 nm, and decreased the number of circles and "racket"-like molecules.
Sogo
J M
JM
Centro de Investigaciones Biologicas, Instituto de Biologia Celular, Velazquez 144, Madrid-6, Spain.
Schneider
I R
IR