Cell Specificity of Histones

Abstract

DURING the course of our investigations^1,2 on the chemistry of the cell nucleus, it was found³ that the basic proteins present in the nuclei of the erythrocytes and liver cells of the salmon bear, in contrast to the protamin (salmine) known to be present in the sperm heads, the complete character of histones. At the same time, significant analytical differences were detected between the histones from the two types of cells. These results suggested to us the possibility that each nucleus possesses a basic protein characteristic of the type of cell of which it forms part. This is certainly true of the sperm head of the salmon, for protamin does not occur in other cell nuclei of this species. It appears also to hold for the nuclei of the erythrocytes and liver cells of this species, for the histones isolated from them exhibited marked differences, quite beyond the limits of analytical error, in their arginine contents. Nevertheless, before generalizing our results it seemed desirable to confirm them and, if possible, to extend them to other species. Unfortunately, we have not yet succeeded, despite many efforts, in obtaining a new specimen of fresh salmon blood. We have, however, examined the histones isolated from cell nuclei of other species with the results recorded below.