Bronner D, Sieberth V, Pazzani C, Smith A, Boulnois G, Roberts I, Jann B, Jann K
Max-Planck-Institut für Immunobiologie, Freiburg, FRG.
FEMS Microbiol Lett. 1993 Nov 1;113(3):279-84. doi: 10.1111/j.1574-6968.1993.tb06527.x.
The genes directing the expression of group II capsules in Escherichia coli are organized into three regions. The central region 2 is type specific and thought to determine the synthesis of the respective polysaccharide, whilst the flanking regions 1 and 3 are common to all group II gene clusters and direct the surface expression of the capsular polysaccharide. In this communication we analyze the involvement of region 1 and 3 genes in the synthesis of the capsular KS polysaccharide. Recombinant E. coli strains harboring all KS specific region 2 genes and having various combinations of region 1 and 3 genes were studied using immunoelectron microscopy. Membranes from these bacteria were incubated with UDP[14C]GlcA and UDPGlcNAc in the absence or presence of KS polysaccharide as an exogenous acceptor. It was found that recombinant strains with only gene region 2 did not produce the K5 polysaccharide. Membranes of such strains did not synthesize the polymer and did not elongate K5 polysaccharide added as an exogenous acceptor. An involvement of genes from region 1 (notably kpsC and kpsS) and from region 3 (notably kpsT) in the K5 polysaccharide synthesis was apparent and is discussed.
指导大肠杆菌中II型荚膜表达的基因被组织成三个区域。中央区域2具有类型特异性，被认为决定了各自多糖的合成，而侧翼区域1和3为所有II型基因簇所共有，并指导荚膜多糖的表面表达。在本通讯中，我们分析了区域1和3的基因在荚膜KS多糖合成中的作用。使用免疫电子显微镜研究了携带所有KS特异性区域2基因并具有区域1和3基因各种组合的重组大肠杆菌菌株。将这些细菌的膜与UDP[14C]GlcA和UDPGlcNAc在不存在或存在KS多糖作为外源受体的情况下孵育。发现仅具有基因区域2的重组菌株不产生K5多糖。此类菌株的膜不合成聚合物，也不延长作为外源受体添加的K5多糖。区域1（特别是kpsC和kpsS）和区域3（特别是kpsT）的基因在K5多糖合成中的作用是明显的，并将进行讨论。
