H1 histones of trout

H1 histones from trout testis, kidney, and liver were purified and characterized. They were extracted directly from tissues by aqueous 0.74 M perchloric acid and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, as well as by ion exchange chromatography employing Bio-Rex 70. While in each case there was a single major H1 band on sodium dodecyl sulfate polyacrylamide gel electrophoresis, the elution patterns from Bio-Rex 70 appeared complex and indicated microheterogeneity. Moreover, by electrophoresis, as well as chromatography, extracts from kidney and liver were observed to contain additional component(s) not found in testis. These components were remarkable H1 subfractions in that they contained methionine and multiple tyrosine residues. Trout testis H1 is unusual in that it has been found to be essentially homogeneous in primary structure (Macleod, A. R., Wong, C. W., and Dixon, G. H. (1977) Eur. J. Biochem. 78, 281-291), while H1 from any other source that has been scrutinized rigorously has shown microheterogeneity. The present observation, that trout tissues generally have multiple H1 subfractions, established that the trout is not exceptional among organisms in possessing a single type of H1. Rather, it is the testis that is unusual among trout tissue in the homogeneity of its H1 population.