Taichman L B
Nucleic Acids Res. 1979;6(5):2029-38. doi: 10.1093/nar/6.5.2029.
Two procedures are described for the fractionation of chromatin containing unsubstituted (LL) DNA and DNA unifilarly substituted with bromodeoxyuridine (HL). The two procedures rely upon the sensitivity of bromodeoxyuridine-containing DNA to UV light to induce either strand breakage or protein crosslinking. When a mixture of LL and HL chromatin is irradiated with UV light, the HL DNA fragments into molecules of smaller molecular weight than the LL DNA and crosslinks more chromosomal protein than the LL DNA. LL and HL chromatin can be fractionated on the basis of size by centrifuging through a neutral sucrose gradient. The HL DNA-protein adducts that are generated by the UV light have a unique buoyant density and may be isolated by isopycnic centrifugation in CS2SO4. The ability to fractionate LL and HL chromatin permits certain studies on the structure of replicating chromatin.
本文描述了两种用于分离含有未取代(LL)DNA和单链溴脱氧尿苷取代DNA(HL)的染色质的方法。这两种方法依赖于含溴脱氧尿苷的DNA对紫外线的敏感性,紫外线可诱导链断裂或蛋白质交联。当LL和HL染色质混合物用紫外线照射时,HL DNA会断裂成分子量比LL DNA小的分子,并且比LL DNA交联更多的染色体蛋白质。LL和HL染色质可以通过在中性蔗糖梯度中离心,根据大小进行分离。紫外线产生的HL DNA-蛋白质加合物具有独特的浮力密度,可以通过在Cs2SO4中进行等密度离心来分离。分离LL和HL染色质的能力使得对复制染色质结构的某些研究成为可能。