Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui, Fukui 910-8507, Japan.
Japan Society for the Promotion of Science for Young Scientists (JSPS), Tokyo 102-0083, Japan.
Biomolecules. 2023 Mar 30;13(4):619. doi: 10.3390/biom13040619.
In , a heterochromatin-like chromatin structure called the silencing region is present at the telomere as a complex of Sir2, Sir3, and Sir4. Although spreading of the silencing region is blocked by histone acetylase-mediated boundary formation, the details of the factors and mechanisms involved in the spread and formation of the boundary at each telomere are unknown. Here, we show that Spt3 and Spt8 block the spread of the silencing regions. Spt3 and Spt8 are members of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, which has histone acetyltransferase activity. We performed microarray analysis of the transcriptome of and strains and RT-qPCR analysis of the transcript levels of genes from the subtelomeric region in mutants in which the interaction of Spt3 with TATA-binding protein (TBP) is altered. The results not only indicated that both Spt3 and Spt8 are involved in TBP-mediated boundary formation on the right arm of chromosome III, but also that boundary formation in this region is DNA sequence independent. Although both Spt3 and Spt8 interact with TBP, Spt3 had a greater effect on genome-wide transcription. Mutant analysis showed that the interaction between Spt3 and TBP plays an important role in the boundary formation.
在 中，端粒处存在一种类似于异染色质的染色质结构，称为沉默区域，它是由 Sir2、Sir3 和 Sir4 组成的复合物。尽管组蛋白乙酰转移酶介导的边界形成阻止了沉默区域的扩散，但每个端粒处涉及的边界扩散和形成的因素和机制的细节尚不清楚。在这里，我们表明 Spt3 和 Spt8 阻止了沉默区域的扩散。Spt3 和 Spt8 是 Spt-Ada-Gcn5-乙酰转移酶（SAGA）复合物的成员，该复合物具有组蛋白乙酰转移酶活性。我们对 和 菌株的转录组进行了微阵列分析，并对 TBP 相互作用改变的突变体中来自端粒区的基因的转录水平进行了 RT-qPCR 分析。结果不仅表明 Spt3 和 Spt8 都参与了 TBP 在染色体 III 右臂上的边界形成，而且该区域的边界形成与 DNA 序列无关。尽管 Spt3 和 Spt8 都与 TBP 相互作用，但 Spt3 对全基因组转录的影响更大。突变体分析表明，Spt3 与 TBP 之间的相互作用在边界形成中起着重要作用。
