Zuberi A R, Ying C W, Weinreich M R, Ordal G W
Department of Biochemistry, College of Medicine, University of Illinois, Urbana 61820.
J Bacteriol. 1990 Apr;172(4):1870-6. doi: 10.1128/jb.172.4.1870-1876.1990.
A cloned chemotaxis operon has been characterized. Thirteen representative che mutations from different complementation groups were localized on the physical map by recombination experiments. The use of integration plasmids established that at least 10 of these complementation groups within this locus are cotranscribed. An additional three complementation groups may form part of the same transcript. The direction of transcription and the time of expression were determined from chromosomal che-lacZ gene fusions. The promoter was cloned and localized to a 3-kilobase fragment. Expression of beta-galactosidase from this promoter was observed primarily during the logarithmic phase of growth. Three-factor PBS1 cotransduction experiments were performed to order the che locus with respect to adjacent markers. The cheF141 mutation is 70 to 80% linked to pyrD1. This linkage is different from that reported previously (G. W. Ordal, D. O. Nettleton, and J. A. Hoch, J. Bacteriol. 154:1088-1097, 1983). The cheM127 mutation is 57% linked by transformation to spcB3. The gene order determined from all crosses is pyrD-cheF-cheM-spcB.
一个克隆的趋化操纵子已得到表征。通过重组实验将来自不同互补群的13个代表性che突变定位在物理图谱上。整合质粒的使用表明，该位点内至少10个这些互补群是共转录的。另外三个互补群可能构成同一转录本的一部分。转录方向和表达时间由染色体che-lacZ基因融合确定。启动子被克隆并定位到一个3千碱基的片段上。主要在对数生长期观察到该启动子驱动的β-半乳糖苷酶的表达。进行了三因子PBS1共转导实验以确定che位点相对于相邻标记的顺序。cheF141突变与pyrD1的连锁率为70%至80%。这种连锁与先前报道的不同（G. W. 奥尔德尔、D. O. 内特尔顿和J. A. 霍克，《细菌学杂志》154:1088 - 1097，1983）。cheM127突变通过转化与spcB3的连锁率为57%。从所有杂交实验确定的基因顺序是pyrD-cheF-cheM-spcB。
