Replication supercoiling control

Nucleoids are nuclei-like structures produced from cells lysed with nonionic detergents in the presence of high salt concentrations. By this treatment, histones and most of the nonhistone proteins are removed [3], They contain naked, histone-free DNA, RNA, and a few proteins [1]. DNA is supercoiled and attached to a cage of residual proteins and RNA [5]. This relationship continues during replication and transcription and seems to be sequence specific [5]. Poly(ADP-ribose) is involved in the regulation of the activities of various enzymes, as well as structural proteins, and seems to be involved in the control of DNA and RNA synthesis [9,11]. It was interesting for us to examine whether ADP-ribosylated proteins remained after generation of nucleoids. We foimd out that one of the residual protein fractions (possibly bound to DNA) was ADP-ribosylated. 

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