Wu Pei-Yun Jenny, Winston Fred
Department of Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
Mol Cell Biol. 2002 Aug;22(15):5367-79. doi: 10.1128/MCB.22.15.5367-5379.2002.
The Saccharomyces cerevisiae SAGA complex is required for the normal transcription of a large number of genes. Complex integrity depends on three core subunits, Spt7, Spt20, and Ada1. We have investigated the role of Spt7 in the assembly and function of SAGA. Our results show that Spt7 is important in controlling the levels of the other core subunits and therefore of SAGA. In addition, partial SAGA complexes containing Spt7 can be assembled in the absence of both Spt20 and Ada1. Through biochemical and genetic analyses of a series of spt7 deletion mutants, we have identified a region of Spt7 required for interaction with the SAGA component Spt8. An adjacent Spt7 domain was found to be required for a processed form of Spt7 that is present in a previously identified altered form of SAGA called SLIK, SAGA(alt), or SALSA. Analysis of an spt7 mutant with greatly reduced levels of SLIK/SAGA(alt)/SALSA suggests a subtle role for this complex in transcription that may be redundant with a subset of SAGA functions.
酿酒酵母SAGA复合物是大量基因正常转录所必需的。复合物的完整性取决于三个核心亚基，即Spt7、Spt20和Ada1。我们研究了Spt7在SAGA组装和功能中的作用。我们的结果表明，Spt7对于控制其他核心亚基的水平以及SAGA的水平很重要。此外，在没有Spt20和Ada1的情况下，可以组装含有Spt7的部分SAGA复合物。通过对一系列spt7缺失突变体的生化和遗传分析，我们确定了Spt7与SAGA组分Spt8相互作用所需的一个区域。发现一个相邻的Spt7结构域是一种加工形式的Spt7所必需的，这种加工形式的Spt7存在于先前鉴定的一种改变形式的SAGA中，称为SLIK、SAGA(alt)或SALSA。对一个SLIK/SAGA(alt)/SALSA水平大幅降低的spt7突变体的分析表明，该复合物在转录中起微妙作用，可能与SAGA功能的一个子集冗余。
