Losa R, Omari S, Thoma F
Institut für Zellbiologie, ETH-Hönggerberg, Zürich, Switzerland.
Nucleic Acids Res. 1990 Jun 25;18(12):3495-502. doi: 10.1093/nar/18.12.3495.
It was suggested that poly(dA).poly(dT) rich sequences in yeast Saccharomyces cerevisiae act as elements of constitutive promoters by exclusion of nucleosomes (Struhl, K. (1985). Proc. Natl. Acad. Sci. USA 82, 8419-8423). We have mapped the chromatin structure of the pet56-his3-ded1 region in minichromosomes and show that the poly(dA).poly(dT) sequences are located in nuclease sensitive regions. DNA fragments from the nuclease sensitive promoter region of DED1 were used for nucleosome reconstitution in vitro. We show that all sequences can form nucleosome cores and that the poly(dA).poly(dT) sequence can be incorporated in nucleosome cores. The results suggest that the nuclease sensitivity found in vivo is not established by poly(dA).poly(dT) mediated exclusion of nucleosomes.
有人提出，酿酒酵母中富含聚（dA）·聚（dT）的序列通过排除核小体而作为组成型启动子的元件（斯特鲁尔，K.（1985年）。美国国家科学院院刊82，8419 - 8423）。我们已经绘制了微型染色体中pet56 - his3 - ded1区域的染色质结构，并表明聚（dA）·聚（dT）序列位于核酸酶敏感区域。来自DED1核酸酶敏感启动子区域的DNA片段用于体外核小体重建。我们表明所有序列都可以形成核小体核心，并且聚（dA）·聚（dT）序列可以掺入核小体核心中。结果表明，体内发现的核酸酶敏感性不是由聚（dA）·聚（dT）介导的核小体排除所建立的。
