Inokuchi K, Nakayama A, Hishinuma F
Laboratory of Molecular Genetics, Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.
Nucleic Acids Res. 1988 Jul 25;16(14B):6693-711. doi: 10.1093/nar/16.14.6693.
The MF alpha 1 gene of Saccharomyces cerevisiae, a major structural gene for mating pheromone alpha factor, is an alpha-cell-specific gene whose expression is regulated by the mating-type locus, MAT. Two upstream activation sites (UASMF alpha 1s), which are binding sites for an activator protein, MAT alpha 1, mediate alpha-cell-specific expression of this gene. We show here that DNA fragments containing the UASMF alpha 1 region exhibited anomalous slow electrophoretic mobilities on gels at lower temperature, but not at higher temperature, that is characteristic of bent DNA. We confirmed the sequence-directed bend at the UASMF alpha 1 region by employing a circular permutation analysis and a DNA cyclization assay. Deletion analyses revealed the existence of two bends in this region, each of which overlaps each UASMF alpha 1 element. The two bends were almost in phase; they lie in a nearly same plane with a same direction. We also show the existence of sequence-directed bend at the UAS region of the STE3 gene, another alpha-specific gene in S. cerevisiae. These bent DNAs may be involved in transcriptional regulation of this set of genes.
酿酒酵母的MFα1基因是交配信息素α因子的一个主要结构基因，是一个α细胞特异性基因，其表达受交配型基因座MAT调控。两个上游激活位点（UASMFα1s）是激活蛋白MATα1的结合位点，介导该基因的α细胞特异性表达。我们在此表明，含有UASMFα1区域的DNA片段在较低温度下在凝胶上呈现异常缓慢的电泳迁移率，但在较高温度下则没有，这是弯曲DNA的特征。我们通过采用环形置换分析和DNA环化试验证实了UASMFα1区域的序列定向弯曲。缺失分析揭示了该区域存在两个弯曲，每个弯曲与每个UASMFα1元件重叠。这两个弯曲几乎同相；它们位于几乎同一平面且方向相同。我们还表明，酿酒酵母中另一个α特异性基因STE3基因的UAS区域存在序列定向弯曲。这些弯曲的DNA可能参与了这组基因的转录调控。
