caa a22 4500 475765583 CHVBK 20180406123604.0 cr unu---uuuuu 170329e20000101xx s 000 0 eng 10.1007/s007050050002 doi (NATIONALLICENCE)springer-10.1007/s007050050002 Activation of the alfalfa mosaic virus genome by viral coat protein in non-transgenic plants and protoplasts. The protection model biochemically tested [Elektronische Daten] [C. J. Houwing, E. M. J. Jaspars] Summary.:  In non-transgenic host plants and protoplasts alfalfa mosaic virus displays a strong need for coat protein when starting an infection cycle. The "protection model” states that the three viral RNAs must have a few coat protein subunits at their 3′ termini in order to protect them in the host cell against degradation by 3′- to- 5′ exoribonucleases [Neeleman L, Van der Vossen EAG, Bol JF (1993) Virology 196: 883-887]. We demonstrated that the naked genome RNAs are slightly infectious, if the inoculation is done at very high concentrations, or if it is preceded by an additional inoculation with the RNAs 1 and 2 (encoding subunits for the viral RNA polymerase). This could mean that the necessity for protection by coat protein is lost if the RNAs in large quantities can overcome the activity of the degrading enzymes, or are protected by association with the RNA polymerase, respectively. However, after having tested in protoplasts the survival of separately preinoculated naked RNA 1 during several hours before RNA 2 was inoculated, on the one hand, or of simultaneously inoculated RNAs 1 and 2, with cycloheximide in the medium during the first hours after inoculation, on the other hand, we had to conclude that the viral genome RNAs are quite stable in the cell in the absence of coat protein or RNA polymerase, respectively. This invalidates the protection model. Accommodation of the above findings by our published "messenger release model” for genome activation [Houwing CJ, Jaspars EMJ (1993) Biochimie 75: 617-621] is discussed. 2000 Springer-Verlag/, Wien Houwing C. J. Institute of Molecular Plant Sciences, Gorlaeus Laboratories, Leiden University, The Netherlands, NL aut Jaspars E. M. J. Institute of Molecular Plant Sciences, Gorlaeus Laboratories, Leiden University, The Netherlands, NL aut https://doi.org/10.1007/s007050050002 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s007050050002 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Houwing C. J. Institute of Molecular Plant Sciences, Gorlaeus Laboratories, Leiden University, The Netherlands, NL aut NATIONALLICENCE 700 1- Jaspars E. M. J. Institute of Molecular Plant Sciences, Gorlaeus Laboratories, Leiden University, The Netherlands, NL aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer