Nematode chromosomal proteins--II. Fractionation and identification of the histones of Caenorhabditis elegans.

1. Whole histone of the nematode Caenorhabditis elegans has been fractionated into the five main histone fractions by a combination of techniques including selective extraction, gel filtration, ion-exchange chromatography and electrophoresis. 2. The histones were identified on acid urea gels by a comparison of the electrophoretic profiles with those of calf thymus histone. 3. Acid urea gel electrophoresis of histone fraction H1 revealed one major and several minor bands. 4. At least three of these were most likely derived from H1 degradation, however. 5. Stepwise elution with 0.01 and 0.02 N HCl of the slightly lysine rich histones from carboxymethyl cellulose resolved two subfractions of H2B, designated H2B1 and H2B2 respectively. 6. Both H2B subtypes co-electrophoresed in acid urea gels containing 2.5 and 6.25 M urea. 7. The electrophoretic mobility of H2A was marginally higher at 2.5 M urea and identical with that of H2B1 and H2B2 at 6.25 M urea. 8. Molecular interaction considerably reduced the usefulness of molecular size fractionation of nematode histones.