Barton M C, Emerson B M
Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037.
Genes Dev. 1994 Oct 15;8(20):2453-65. doi: 10.1101/gad.8.20.2453.
Regulated gene expression within a complex chromosomal locus requires multiple nuclear processes. We have analyzed the transcriptional properties of the cloned chick beta-globin gene family when assembled into synthetic nuclei made by use of Xenopus egg extracts. Assembly in an erythroid protein environment correctly recapitulates tissue-specific chromatin structure and long-range promoter-enhancer interaction within the chromosomal locus, resulting in beta-globin gene activation. Nucleosome-repressed beta-globin templates can be transcriptionally activated by double-stranded DNA replication in the presence of staged erythroid proteins by remodeling of the chromatin structure within the promoter region and establishment of distal promoter-enhancer communication. The programmed transcriptional state of a gene, as encoded by its chromatin structure and long-range promoter-enhancer interactions, is stable to nuclear decondensation and DNA replication unless active remodeling occurs in the presence of specific DNA-binding proteins.
在一个复杂的染色体位点内调控基因表达需要多个核过程。我们分析了克隆的鸡β-珠蛋白基因家族在利用非洲爪蟾卵提取物构建的合成核中的转录特性。在红细胞蛋白环境中组装能正确重现染色体位点内的组织特异性染色质结构和远距离启动子-增强子相互作用，从而导致β-珠蛋白基因激活。核小体抑制的β-珠蛋白模板可以通过在有阶段特异性红细胞蛋白存在的情况下进行双链DNA复制，通过启动子区域内染色质结构的重塑和远距离启动子-增强子通讯的建立而被转录激活。由其染色质结构和远距离启动子-增强子相互作用所编码的基因的程序化转录状态，对于核解聚和DNA复制是稳定的，除非在特定DNA结合蛋白存在的情况下发生主动重塑。
