Eissenberg J C, Kimbrell D A, Fristrom J W, Elgin S C
Nucleic Acids Res. 1984 Dec 11;12(23):9025-38. doi: 10.1093/nar/12.23.9025.
The chromatin structure of the larval cuticle gene cluster at 44D was characterized in embryos from wild-type (Oregon R) and a variant line (2/3) of Drosophila melanogaster. A major DNase I hypersensitive (DH) site was found between genes II and III in the chromatin, in a position 5' to the transcriptional start of the genes in the cluster. The introduction of a 7.3 kilobase transposable element into the cluster in the 2/3 variant enhanced the sensitivity of the major site in 2/3 chromatin but had no other effect upon the pattern of DH sites associated with the wild-type sequences. The wild-type sequences were packaged into an ordered nucleosome-like array in embryos, as revealed by digestion with the chemical cleavage reagent (methidiumpropyl-EDTA) iron (II) [MPE . Fe(II)]. Nucleolytic cleavage within the transposable element chromatin shows it to be organized in an ordered array punctuated by several DH sites. While the patterns of DNase I hypersensitivity are similar in the vicinity of the direct terminal repeats, the patterns revealed by micrococcal nuclease and MPE . Fe(II) are not, indicating a different chromatin organization of these two identical sequences.
在野生型（俄勒冈R）和黑腹果蝇的一个变异品系（2/3）的胚胎中，对位于44D的幼虫表皮基因簇的染色质结构进行了表征。在染色质中基因II和III之间发现了一个主要的DNA酶I超敏（DH）位点，位于该簇中基因转录起始位点的5'端。在2/3变异品系中，将一个7.3千碱基的转座元件引入该簇，增强了2/3染色质中主要位点的敏感性，但对与野生型序列相关的DH位点模式没有其他影响。如用化学切割试剂（甲基丙基 - EDTA）铁（II）[MPE·Fe（II）]消化所揭示的，野生型序列在胚胎中被包装成有序的核小体样阵列。转座元件染色质内的核酸酶切割显示它以有序阵列形式组织，中间有几个DH位点。虽然在直接末端重复序列附近DNA酶I超敏模式相似，但微球菌核酸酶和MPE·Fe（II）揭示的模式不同，表明这两个相同序列的染色质组织不同。
