Chromatographic studies of nucleic acids. 4. The nucleic acid of the turnip yellow mosaic virus, including a note on the nucleic acid of the tomato bushy stunt virus

Abstract

It was largely because of our interest in the turnip yellow mosaic virus (Markham & Smith, K. M., 1949) that we began our study of nucleic acids.This virus contains about 37 % by weight of ribonucleic acid, which is an unusually high proportion.All the infected plants which we have examined contain, as well as the virus, another characteristic and related protein in an amount equivalent to 25-30 % of the weight of the virus nucleoprotein.This protein, as far as we know, cannot be separated from the virus by any method other than fractional centrifuging, as the two proteins differ very little, if at all, in their solubilities in various solutions, in electrical charge and in their size, shape and general surface properties.This second protein appears to be the virus nucleo- protein minus its nucleic acid, and it is non-infectious.It is a very poor antigen in rabbits, although it combines readily with antiserum to the nucleo- protein, which itself is an excellent antigen.In these two properties, ability to cause a disease and ability to cause antibody production in rabbits, we would appear to have biological activities associated with a nucleic acid, and with a view to obtaining further information about the function of nucleic acid in viruses we have undertaken the analysis of several virus nucleic acids.We describe in the following paper several refinements of our earlier techniques and we have confirmed most of our findings by orthodox micro- analytical procedures, which, combined with chro- matographic methods, can be used to analyse ribonucleic acids without the need for an ultraviolet spectrophotometer.