Abstract: | In vivo uncoating of tobacco mosaic virus (TMV) was studied. As Shaw had reported, initiation of uncoating reaction takes place very efficiently. Coat protein is removed from the virus as a peptide which is precipitable with trichloroacetic acid. Short rod particles with partly exposed RNA are thus formed. Further uncoating to coat protein-free TMV-RNA (28S) seems to take place with very low efficiency which is comparable to that of formation of local lesions on the inoculated leaf. From the data on the intracellular distribution of these products of uncoating reaction, mechanisms and significance of these reactions are discussed. |