SV40 minichromosome

This problem first emerged from the necessity to reconcile topological and structural data of nucleosomes and chromatin. As soon as a minichromosome could be reconstituted from pure DNA and histones, the total reduction of the DNA linking number (Lk) was found to be equal to the number of nucleosomes, which was also true for the native Hl-bearing SV40 minichromosome [12]. On the other hand, the first low-resolution crystal of the core particle showed that DNA was wrapped with 1 3/4 turns of a left-handed superhelix. Assuming linker DNAs... 

The C-terminal domain of HMGN was required for transcriptional enhancement in both SV40 minichromosomes and in minichromosomes assembled using... 

A second model for HMGN action is that it counteracts chromatin compaction by linker histones. The ability of HMGN proteins to unfold SV40 minichromosomes and stimulate transcription from them is dependent on the presence of linker histones, and the data is consistent with HMGN counteracting the repressive... 

Glotov, B.O., Rudin, A.V., and Severin, E.S. (1982) Conditions for sliding of nucleosomes along DNA SV40 minichromosomes. Biochim. Biophys. Acta 696, 275-284. 

Another difference between bacterial and eukaryotic replication is the presence of nucleosomes in eukaryotes. Some evidence suggests that nucleosomes may open and close to allow replication forks to pass through.509 Studies of SV40 minichromosomes indicate that passage of the replication machinery does destabilize nucleosomes, which must be partially reconstructed about 260 nucleotides past the elongation point.510 Another factor is the variable extent and location of modifications to histones, in particular to... 

Fig. 12.15. Effects of polyamines on the OH-induced strand-breakage of SV40 DNA (putrescine open triangles, spermine filled diamonds) and SV40 minichromosomes (spermine open squares) according to Newton et al. (1996, with permission)...

Figure 9. Electron micrograph of an SV40 minichromosome that shows a stretch of the genome devoid of nucleosomes. This gap has been mapped from the Bgl 1 site to about 0.74 on the physical map. The nucleosomes appear as white circular clusters along the circular DNA. (Reproduced with permission from Ref. 50. Copyright 1980, Massachusetts Institute of Technology.)...

Cohen JJ, Catino DM, Petzold SJ, Berger NA (1982) Activation of poly (adenosine diphosphate ribose) polymerase by SV40 minichromosomes effects of deoxyribonucleic acid damage and histone HI. Biochemistry 21 4931-4940... 

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