Glöckner G, Beck C F
Institut für Biologie III, Universität Freiburg, Germany.
Plant J. 1997 Sep;12(3):677-83. doi: 10.1046/j.1365-313x.1997.00677.x.
The Chlamydomonas reinhardtii mutant lrg2 exhibits a partial defect in the blue-light activated signal transduction chain that controls gametogenesis. By genomic complementation, a cosmid clone that corrects the lrg2 phenotype was isolated. The smallest fragment of this cosmid that gave complementation was used in RFLP analysis, which revealed that the cloned gene was not linked to the LRG2 locus. The sequence of the genomic clone and a cDNA of this gene, which we named LRG5, was determined. Although no significant homology with sequences in the databases was found, the nuclear localization signal and the presence of negatively and positively charged domains suggests a function for the LRG5 protein in the regulation of transcription. The correction of the lrg2 phenotype is probably caused by overexpression of the LRG5 gene in the transformants, as these expressed a level of LRG5 approximately twofold higher than wild-type or mutant strains. Southern blot analysis provided evidence for the existence of homologous sequences in other green algae as well as in higher plants, suggesting a conserved function for the LRG5 protein.
莱茵衣藻突变体lrg2在控制配子发生的蓝光激活信号转导链中表现出部分缺陷。通过基因组互补，分离出一个纠正lrg2表型的黏粒克隆。该黏粒产生互补作用的最小片段用于RFLP分析，结果表明克隆的基因与LRG2基因座不连锁。确定了该基因的基因组克隆和cDNA序列，我们将其命名为LRG5。虽然未发现与数据库中的序列有明显同源性，但核定位信号以及正负电荷结构域的存在表明LRG5蛋白在转录调控中具有一定功能。lrg2表型的纠正可能是由于转化体中LRG5基因的过表达，因为这些转化体中LRG5的表达水平比野生型或突变体菌株高约两倍。Southern印迹分析证明在其他绿藻以及高等植物中存在同源序列，这表明LRG5蛋白具有保守功能。
