Shakhov A N, Nedospasov S A, Georgiev G P
Nucleic Acids Res. 1982 Jul 10;10(13):3951-65. doi: 10.1093/nar/10.13.3951.
T prove sequence-specific chromatin structure of SV40 minichromosome, we further modified previously described hybridization mapping. Actually (i) the digestion patterns by two nucleases (micrococcal and DNAase II) were compared and (ii) the kinetics of nuclease digestion was analyzed from early time points when only a fraction of minichromosomes was cleaved once to longer digestions when oligo- and mononucleosomal bands appeared. DNAase II is shown to possess certain sequence specificity different from that of micrococcal nuclease. The major finding is that DNAase II preferentially cleaves the SV40 minichromosome at a distinct region of the genome known as 72 bp modulator element. Other hypersensitive sites are located near the replication origin and T-ag binding site II and also near BamHI site where termination of replication and "late" transcription occurs. Micrococcal nuclease splits the BglI-Hpaii region in a different manner.
为了证明SV40微型染色体的序列特异性染色质结构，我们进一步改进了先前描述的杂交图谱分析方法。具体如下：（i）比较了两种核酸酶（微球菌核酸酶和DNA酶II）的消化模式；（ii）分析了核酸酶消化的动力学，从仅一小部分微型染色体被切割一次的早期时间点，到寡核小体和单核小体条带出现的较长消化时间。结果表明，DNA酶II具有与微球菌核酸酶不同的特定序列特异性。主要发现是，DNA酶II优先在基因组中一个称为72 bp调节元件的特定区域切割SV40微型染色体。其他超敏感位点位于复制起点和T抗原结合位点II附近，也位于复制终止和“晚期”转录发生的BamHI位点附近。微球菌核酸酶以不同方式切割BglI-Hpaii区域。
