Manney T R
J Bacteriol. 1983 Jul;155(1):291-301. doi: 10.1128/jb.155.1.291-301.1983.
We have demonstrated and partially characterized the genetic control and pheromonal regulation of a soluble activity, produced only by mating-type a cells, that inhibits the action of the alpha mating pheromone, alpha-factor, on mating-type a cells. This activity was found to be associated with a heat-stable protein and to be secreted by MATa BAR1, mat alpha 2 BAR1, and mat alpha 1 mat alpha 2 BAR1 strains, but not by MAT alpha BAR1, MATa/MAT alpha BAR1, mat alpha 1 BAR1, or MATa barl strains, demonstrating that it is under the control of both the MAT alpha 2 and the BAR1 genes. Secretion of this activity was also found to be stimulated to as much as five times the basal level by exposure of the cells to alpha-factor. This stimulation was maximal after 6 h at a pheromone concentration of approximately 2 U/ml. An assay for this activity was developed by using a refined, quantitative assay for alpha-factor. The pheromone activity of samples added to wells in an agar plate was related to the size of the halo of growth inhibition produced in a lawn of mutant cells that are abnormally sensitive. The alpha-factor-inhibiting activity was related to a reduction of the halo size when active samples were added to the lawn. Although the assay for alpha-factor was found to be relatively insensitive to pH over a range of several units, the alpha-factor-inhibiting activity displayed a sharp pH optimum at approximately 6.5. The properties of this activity have important implications concerning the role of the BAR1 gene product in recovery of mating-type a cells from cell division arrest by alpha-factor.
我们已经证明并部分表征了一种仅由a交配型细胞产生的可溶性活性物质的遗传控制和信息素调节作用，该物质可抑制α交配信息素α-因子对a交配型细胞的作用。发现这种活性与一种热稳定蛋白相关，并由MATa BAR1、matα2 BAR1和matα1 matα2 BAR1菌株分泌，但不由MATα BAR1、MATa/MATα BAR1、matα1 BAR1或MATa barl菌株分泌，这表明它受MATα2和BAR1基因的控制。还发现，将细胞暴露于α-因子可使这种活性的分泌刺激至基础水平的五倍之多。在信息素浓度约为2 U/ml的情况下，6小时后这种刺激作用达到最大。通过使用一种改进的α-因子定量测定法，开发了一种针对这种活性的测定方法。添加到琼脂平板孔中的样品的信息素活性与在异常敏感的突变细胞菌苔中产生的生长抑制晕圈大小有关。当向菌苔中添加活性样品时，α-因子抑制活性与晕圈大小的减小有关。尽管发现α-因子测定法在几个单位的pH范围内对pH相对不敏感，但α-因子抑制活性在约6.5时显示出明显的pH最佳值。这种活性的特性对于BAR1基因产物在a交配型细胞从α-因子引起的细胞分裂停滞中恢复的作用具有重要意义。
