Ref ID : 3962
Peter J. Rizzo; Analysis of Histones from the Endosymbionts Nucleus of a Binucleate Dinoflagellate. J.Protozool. 29(1):98-103, 1982
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Histones were prepared from chromatin of the eukaryotic (endosymbiont) nucleus of Peridinium balticum (Levander) Lemmermann. The amino acid composition of whole histone was rich in lysine and similar to that of Olisthodiscus luteus and Euglena gracilis. Electrophoretic analysis of these proteins in acidic-urea disc gels revealed four major bands: one with a mobility slightly lower than that of calf thymus H1; and three others which comigrated with calf H2B, H2A, and H4, respectively. The low mobility band was soluble in 5% perchloric acid and was sensitive to FeCl3 destaining. Electrophoresis in slab gels containing 0.1% SDS revealed five major components, with approximate molecular weights of 23,000, 20,000, 15,000, 13,000, and 11,000, respectively. The 15,000 and 11,000 dalton histones had mobilities identical to those of calf H3 and H4, respectively. The two highest molecular weight components were soluble in 5% perchloric acid. No bands were found to comigrate with calf H2A or H2B but a band was present that migrated to a position intermediate between calf H2A and H4 (13,000 dalton histone), two-dimensional gels consisting of acidic-urea gels in the first dimension and SDS gels in the second dimension revealed that the 20,000 dalton component and the 13,000 dalton component are not resolved in the acidic-urea gel. As a working hypothesis, it is suggested that two of the five bands seen in SDS gels represent an H1-like doublet, and two are analagous to H3 and H4, respectively. The remaining histone may replace H2A and H2B.