Zornetzer M S, Stein G S
Proc Natl Acad Sci U S A. 1975 Aug;72(8):3119-23. doi: 10.1073/pnas.72.8.3119.
Chromatin was prepared from isolated nuclei of proliferating and differentiated cultures of C1300 mouse neuroblastoma cells. Differentiation was induced by serum withdrawal or treatment with dibutyryl cyclic AMP. The ability to support DNA-dependent RNA synthesis when assayed in a cell-free system is three times greater for chromatin from proliferating cells. Histones isolated from proliferating and differentiated cells were fractionated electrophoretically. The relative amounts of proteins present in the five major histone fractions were similar. In contrast, there were significant differences in the nonhistone chromosomal proteins synthesized and associated with the genome of proliferating and differentiating neuroblastoma cells. Such differences are reflected by modifications in the electrophoretic banding patterns and in incorporation of [3H]tryptophan into various molecular weight classes of nonhistone chromosomal polypeptides. A functional relationship between changes in the nonhistone chromosomal proteins and variations in the transcriptional activity accompanying differentiation of neuroblastoma cells may exist.
从增殖和分化的C1300小鼠神经母细胞瘤细胞的分离细胞核中制备染色质。通过血清去除或用二丁酰环磷腺苷处理诱导分化。在无细胞系统中进行测定时，增殖细胞染色质支持DNA依赖性RNA合成的能力是分化细胞染色质的三倍。从增殖和分化细胞中分离的组蛋白通过电泳进行分级分离。五个主要组蛋白组分中存在的蛋白质相对量相似。相比之下，增殖和分化的神经母细胞瘤细胞合成的与基因组相关的非组蛋白染色体蛋白存在显著差异。这种差异反映在电泳条带模式的改变以及[3H]色氨酸掺入不同分子量类别的非组蛋白染色体多肽中。非组蛋白染色体蛋白的变化与神经母细胞瘤细胞分化伴随的转录活性变化之间可能存在功能关系。
