Green L, Schlaffer I, Wright K, Moreno M L, Berand D, Hager G, Stein J, Stein G
Proc Natl Acad Sci U S A. 1986 Apr;83(8):2315-9. doi: 10.1073/pnas.83.8.2315.
We have constructed a recombinant plasmid that includes a cell cycle-dependent human H4 histone gene with 650 base pairs of 5' and 900 base pairs of 3' flanking sequences and the 69% transforming fragment of bovine papilloma virus. When transfected into C127 mouse cells, this plasmid is maintained as a stable episome with approximately 20 copies per cell. Micrococcal nuclease digestion indicates that the episomal human histone gene is packaged as chromatin. The human H4 histone transcript is initiated at the correct 5' start site and undergoes selective destabilization when DNA synthesis is inhibited. When C127 cells containing the episomal H4 histone gene are synchronized, the human H4 histone mRNA levels are regulated coordinately with DNA replication and parallel those of transcripts from the murine chromosomal H4 histone genes. Our results suggest that the regulatory sequences and/or regulatory molecules associated with murine and human histone genes are compatible. The human histone gene-bovine papillomavirus episome is therefore a viable system for studying cell cycle-regulated histone gene expression under conditions where control is not influenced at the site of chromosomal integration by cis-acting elements of genes normally not contiguous.
我们构建了一种重组质粒，它包含一个细胞周期依赖性的人类H4组蛋白基因，该基因带有650个碱基对的5'侧翼序列和900个碱基对的3'侧翼序列，以及牛乳头瘤病毒69%的转化片段。当转染到C127小鼠细胞中时，该质粒作为稳定的附加体得以维持，每个细胞约有20个拷贝。微球菌核酸酶消化表明，附加体人类组蛋白基因被包装成染色质。人类H4组蛋白转录本在正确的5'起始位点起始，并且在DNA合成被抑制时会发生选择性降解。当含有附加体H4组蛋白基因的C127细胞同步化时，人类H4组蛋白mRNA水平与DNA复制协调调节，并且与小鼠染色体H4组蛋白基因的转录本水平平行。我们的结果表明，与小鼠和人类组蛋白基因相关的调控序列和/或调控分子是相容的。因此，人类组蛋白基因 - 牛乳头瘤病毒附加体是一种可行的系统，可用于在不受正常不相邻基因的顺式作用元件在染色体整合位点影响控制的条件下，研究细胞周期调控的组蛋白基因表达。
