Nose K, Tanaka A, Okamoto H
J Biochem. 1981 Jul;90(1):103-11. doi: 10.1093/oxfordjournals.jbchem.a133438.
RNA polymerase II was purified from mouse Ehrlich ascites tumor cells, and was used to transcribe chromatin from Friend leukemic cells at various stages of induction. The transcription was entirely dependent on exogenous RNA polymerase, and was inhibited by actinomycin D, or a low dose of alpha-amanitin. Globin-specific sequences of the transcripts were determined by hybridization of 3H-labeled transcripts with plasmid DNA immobilized on filters. When chromatin from uninduced cells was used, less than 0.01% of the total radioactivity was retained on the globin DNA-filters, whereas about 0.05% was retained when chromatin was made from induced cells. This value was about one-ninth of the content of cytoplasmic globin mRNA which was pulse-labeled in induced cells. The transcription of whole chromatin or globin genes was inhibited almost completely by a rifampicin derivative, but in the case of chromatin, both sense and anti-sense strands of globin were transcribed. From these results, it is suggested that isolated chromatin retains some native conformation but is transcribed aberrantly.
从小鼠艾氏腹水瘤细胞中纯化出RNA聚合酶II，并用于转录处于诱导不同阶段的Friend白血病细胞的染色质。转录完全依赖于外源RNA聚合酶，并受到放线菌素D或低剂量α-鹅膏蕈碱的抑制。通过将3H标记的转录本与固定在滤膜上的质粒DNA杂交来确定转录本的珠蛋白特异性序列。当使用未诱导细胞的染色质时，总放射性中不到0.01%保留在珠蛋白DNA滤膜上，而当使用诱导细胞制备的染色质时，约0.05%被保留。该值约为诱导细胞中脉冲标记的细胞质珠蛋白mRNA含量的九分之一。利福平衍生物几乎完全抑制了整个染色质或珠蛋白基因的转录，但就染色质而言，珠蛋白的有义链和反义链均被转录。从这些结果表明，分离的染色质保留了一些天然构象，但转录异常。
