Mauël C, Young M, Monsutti-Grecescu A, Marriott S A, Karamata D
Institut de Génétique et Biologie Microbiennes, Lausanne, Switzerland.
Microbiology (Reading). 1994 Sep;140 ( Pt 9):2279-88. doi: 10.1099/13500872-140-9-2279.
Five of the genes known to encode the synthesis of poly(glycerol phosphate), the major teichoic acid of Bacillus subtilis 168, are organized in two divergently transcribed operons (a divergon), denoted tagAB and tagDEF. To monitor their expression, the 399 bp intergenic region separating the first structural genes of these operons was fused, in both orientations, to a lacZ reporter gene, allowing measurement of promoter activity under specific physiological conditions. Under all experimental conditions, tagA and tagD appeared coordinately expressed, the level of tagD being always higher than that of tagA. No influence of the chromosomal context was observed. Phosphate limitation was accompanied by reduced tag gene expression. Following the onset of sporulation, expression of tag genes diminished rapidly and was essentially abolished by stage II. During germination, the activity of tag genes was detectable before the rise in culture turbidity associated with spore outgrowth. In contrast to tagC (dinC), the expression of which is DNA-damage-inducible, the induction of SOS functions had no effect on tagA and tagD gene expression. The biological significance of these results is discussed.
已知编码聚（甘油磷酸）合成的五个基因，即枯草芽孢杆菌168的主要磷壁酸，被组织成两个反向转录的操纵子（一个反向操纵子），分别为tagAB和tagDEF。为了监测它们的表达，将分隔这些操纵子第一个结构基因的399 bp基因间区域以两种方向与lacZ报告基因融合，从而能够在特定生理条件下测量启动子活性。在所有实验条件下，tagA和tagD似乎是协同表达的，tagD的水平总是高于tagA。未观察到染色体背景的影响。磷酸盐限制伴随着tag基因表达的降低。在芽孢形成开始后，tag基因的表达迅速减少，到第二阶段基本消失。在萌发过程中，在与孢子萌发相关的培养物浊度升高之前就可检测到tag基因的活性。与tagC（dinC）的表达不同，tagC的表达是DNA损伤诱导型的，SOS功能的诱导对tagA和tagD基因的表达没有影响。讨论了这些结果的生物学意义。
