細菌の運動性突然変異体(motA、motB)についての分子遺伝学的解析

概要

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The Mot complex is regarded as a half of the bacterial flagellar motor. It is composed of MotA and MotB proteins, the products of motA and motB genes. From Salmonella typhimurium nonmotile and slow swimming mot mutants were isolated:the former as resistant clones to flagellotropic phage_x and the latter as pseudorevertants of a nonchemotactic strain SJW2811 carrying a mutation in the switch gene fliG. SJW2811 shows inverse smooth swimming in liquid medium but can not spread in semisolid medium. Slow swimming pseudorevertants were found as small swarmers in semisolid medium. Mutated genes in 206 mot mutants were identified as motA or motB: 139 as motA, 65 as motB, and 2ΔmotAB. 87 mutants were analysed at DNA level and amino acid changes in MotA and MotB proteins were deduced. More than 2/3 mutations were located to transmembrane segments in either protein. The 2nd mutations in psudorevertants were transduced into a fliG^+ strain. Resulted mot strains manifested variety of phenotypes, e.g. swimming rate, swarming rate, and temperature sensitivity. Meaning of their phenotypes was discussed in relation to the structure and function of Mot proteins.
明治大学の論文