Ozsarac N, Bhattacharyya M, Dawes I W, Clancy M J
School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney, Australia.
Gene. 1995 Oct 16;164(1):157-62. doi: 10.1016/0378-1119(95)00438-c.
The SPR3 gene is selectively activated only during the sporulation phase of the Saccharomyces cerevisiae (Sc) life cycle. The predicted amino acid (aa) sequence has homology to microfilament proteins that are involved in cytokinesis and other proteins of unknown function. These include the products of Sc cell division cycle (CDC) genes involved in bud formation (Cdc3p, Cdc10p, Cdc11p and Cdc12p), Candida albicans proteins that accumulate in the hyphal phase (CaCdc3p and CaCdc10p), mouse brain-specific (H5p) and lymphocyte (Diff6p) proteins, Drosophila melanogaster (Dm) protein Pnutp (which is localized to the cleavage furrow of dividing cells), a Diff6p homologue (DmDiff6p), and the Sc septin protein (Sep1hp), a homologue of the 10-nm filament proteins of Sc. One strongly conserved region contains a potential ATP-GTP-binding domain. Primer extension analysis revealed six major transcription start points (tsp) beginning at -142 relative to the ATG start codon. The sequence immediately upstream from the tsp contains consensus binding sites for the HAP2/3/4 and ABFI transcription factors, a T-rich sequence and two putative novel elements for mid to late sporulation, termed SPR3 and PAL. Electrophoretic mobility shift assay (EMSA) and footprint analyses demonstrated that the ABFI protein binds to a region containing the putative ABFI site in vitro, and site-directed mutagenesis showed that the ABFI motif is essential for expression of SPR3 at the appropriate stage in sporulating cells.
SPR3基因仅在酿酒酵母（Sc）生命周期的孢子形成阶段被选择性激活。预测的氨基酸（aa）序列与参与胞质分裂的微丝蛋白以及其他功能未知的蛋白具有同源性。这些蛋白包括参与芽形成的Sc细胞分裂周期（CDC）基因的产物（Cdc3p、Cdc10p、Cdc11p和Cdc12p）、在菌丝阶段积累的白色念珠菌蛋白（CaCdc3p和CaCdc10p）、小鼠脑特异性（H5p）和淋巴细胞（Diff6p）蛋白、果蝇（Dm）蛋白Pnutp（定位于分裂细胞的分裂沟）、Diff6p同源物（DmDiff6p）以及Sc septin蛋白（Sep1hp），后者是Sc的10纳米丝状蛋白的同源物。一个高度保守的区域包含一个潜在的ATP - GTP结合结构域。引物延伸分析揭示了相对于ATG起始密码子从 - 142开始的六个主要转录起始点（tsp）。tsp上游紧邻的序列包含HAP2/3/4和ABFI转录因子的共有结合位点、一个富含T的序列以及两个推测的孢子形成中后期的新元件，分别称为SPR3和PAL。电泳迁移率变动分析（EMSA）和足迹分析表明，ABFI蛋白在体外与包含推测的ABFI位点的区域结合，定点诱变显示ABFI基序对于SPR3在孢子形成细胞的适当阶段表达至关重要。
