Levy S, Childs G, Kedes L
Cell. 1978 Sep;15(1):151-62. doi: 10.1016/0092-8674(78)90091-0.
RNA transcribed in isolated sea urchin nuclei and assayed by hybridization to histone genes cloned in E. coli contains sequences homologous to each of the five histone genes. Histone RNA is synthesized exclusively from the same DNA strand which is the template in vivo. Synthesis of the histone gene transcripts is sensitive to alpha-amanitin concentrations which inhibit RNA polymerase II activity. The fraction of histone RNA synthesized in vitro is comparable at two developmental stages to the fraction synthesized in vivo. The nuclear histone transcripts contain sequences homologous to spacer DNA regions present between the coding regions of the 6500 base pair (bp) histone gene repeat unit. The transcription of spacer sequences was demonstrated by hybridization of the nuclear transcripts to subcloned spacer DNA. Although the bulk of the RNA transcripts are greater than 2000 bases long, the histone-specific transcripts are of discrete sizes ranging from 100 bases to about 1100 bases long. Each histone gene hybridizes with at least one of the larger transcripts and with a different subset of smaller RNAs. We do not detect any giant polycistronic transcript spanning the entire histone repeat unit.
在分离出的海胆细胞核中转录的RNA，通过与克隆于大肠杆菌中的组蛋白基因杂交进行分析，结果显示其含有与五个组蛋白基因中的每一个都同源的序列。组蛋白RNA仅从体内作为模板的同一条DNA链合成。组蛋白基因转录本的合成对抑制RNA聚合酶II活性的α-鹅膏蕈碱浓度敏感。在两个发育阶段，体外合成的组蛋白RNA的比例与体内合成的比例相当。细胞核中的组蛋白转录本含有与6500碱基对（bp）组蛋白基因重复单元编码区之间存在的间隔DNA区域同源的序列。通过将细胞核转录本与亚克隆的间隔DNA杂交，证实了间隔序列的转录。尽管大部分RNA转录本长度超过2000个碱基，但组蛋白特异性转录本的大小是离散的，范围从100个碱基到约1100个碱基长。每个组蛋白基因与至少一个较大的转录本以及不同的较小RNA子集杂交。我们未检测到跨越整个组蛋白重复单元的任何巨大多顺反子转录本。
