Englert C, Wanner G, Pfeifer F
Max-Planck-Institut für Biochemie, Martinsried, Germany.
Mol Microbiol. 1992 Dec;6(23):3543-50. doi: 10.1111/j.1365-2958.1992.tb01789.x.
A series of deletions introduced into the gvp gene cluster of Haloferax mediterranei, comprising 14 genes involved in gas vesicle synthesis (mc-vac-region), was investigated by transformation experiments. Gas vesicle production and the expression of the gvpA gene encoding the major gas vesicle protein, GvpA, was monitored in each Haloferax volcanii transformant. Whereas transformants containing the entire mc-vac-region produced gas vesicles (Vac+), various deletions in the region 5' to gvpA (encompassing gvpD-gvpM) or 3' to gvpA (containing gvpC, gvpN and gvpO) revealed Vac- transformants. All these transformants expressed gvpA and contained the 8 kDa GvpA protein as shown by Western analysis. However, transformants containing the gvpA gene by itself indicated a lower level of GvpA than observed with each of the other transformants. None of these transformants containing deletion constructs assembled the GvpA protein into gas vesicles. In contrast, transformants containing a construct carrying a 918 bp deletion internal to gvpD exhibited a tremendous gas vesicle overproduction, suggesting a regulatory role for the gvpD gene or its product. This is the first assignment of a functional role for one of the 13 halobacterial gvp genes found in addition to gvpA that are involved in the synthesis of this unique structure.
通过转化实验研究了引入到地中海嗜盐菌gvp基因簇中的一系列缺失，该基因簇包含14个参与气荚膜合成的基因（mc-vac区域）。在每个火山嗜盐菌转化体中监测气荚膜的产生以及编码主要气荚膜蛋白GvpA的gvpA基因的表达。含有完整mc-vac区域的转化体产生气荚膜（Vac+），而gvpA 5'端区域（包括gvpD-gvpM）或gvpA 3'端区域（包含gvpC、gvpN和gvpO）的各种缺失则产生了Vac-转化体。如蛋白质免疫印迹分析所示，所有这些转化体均表达gvpA并含有8 kDa的GvpA蛋白。然而，仅含有gvpA基因的转化体显示出的GvpA水平低于其他转化体。这些含有缺失构建体的转化体均未将GvpA蛋白组装进气荚膜中。相反，含有在gvpD内部携带918 bp缺失的构建体的转化体表现出气荚膜的大量过量产生，这表明gvpD基因或其产物具有调节作用。这是除gvpA之外发现的13个嗜盐细菌gvp基因中第一个被赋予功能作用的基因，这些基因参与了这种独特结构的合成。
