Rat liver HMG1: a physiological nucleosome assembly factor - PubMed (original) (raw)

Rat liver HMG1: a physiological nucleosome assembly factor

C Bonne-Andrea et al. EMBO J. 1984 May.

Abstract

Incubation of rat liver single-stranded DNA-binding protein HMG1 with the four core histones at 0.15 M NaCl favors histone association primarily into tetramers and, to a lesser extent, into octamers. The assembly of pre-formed histone-HMG1 complexes with DNA yields nucleosome-like subunits which satisfy most of the criteria defining native core particles: (i) the circular DNA extracted from the complexes is supercoiled indicating that the initially relaxed DNA acquired superhelical turns during complex formation in the presence of topoisomerase I; (ii) the digestion of the complexes with micrococcal nuclease yields a DNA fragment of approximately 140 bp in length; (iii) electron microscopy of the reconstituted complexes shows a beaded structure with the DNA wrapped around the histone cores, leading to a reduction in the contour length of the genome compared with free DNA. Moreover, in the presence of HMG1, nucleosome assembly occurs rapidly at 0.15 M NaCl. Therefore, in addition to its DNA-binding properties, HMG1 mediates the assembly of nucleosomes in vitro under conditions of physiological ionic strength. The possible involvement of these properties in the DNA replication process is discussed.

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References

    1. J Mol Biol. 1967 Jun 14;26(2):365-9 - PubMed
    1. Proc Natl Acad Sci U S A. 1970 Jul;66(3):651-6 - PubMed
    1. Nature. 1970 Aug 15;227(5259):680-5 - PubMed
    1. J Ultrastruct Res. 1971 Apr;35(1):147-67 - PubMed
    1. Anal Biochem. 1973 Dec;56(2):502-14 - PubMed

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