Mamat U, Rietschel E T, Schmidt G
Forschungsinstitut Borstel, Institut für Experimentelle Biologie und Medizin, Germany.
Mol Microbiol. 1995 Mar;15(6):1115-25. doi: 10.1111/j.1365-2958.1995.tb02285.x.
Lysogenic Acetobacter methanolicus strains carrying the prophage Acm1 were found to be unable to synthesize both the capsular polysaccharide (CPS) and the O-specific side-chain of lipopolysaccharide (LPS) and to represent rough variants of the host bacterium. A 262 bp DNA fragment of phage Acm1, obviously required for interference with LPS biosynthesis, was cloned and expressed in Escherichia coli. Independently of the O-type, transformation of various E. coli strains with the recombinant DNA resulted in a suppression of biosynthesis of the O-specific chains. The DNA fragment of phage Acm1 contained three very short open reading frames of 21, 24, and 36 bp. However, attempts to express phage-encoded peptides were not successful. Instead, the Acm1-derived DNA fragment was shown to code for the synthesis of a trans-acting RNA molecule of 97 nucleotides, designated lbi (LPS biosynthesis-interfering) RNA. This RNA contains sequence complementarity to E. coli target RNA sequences and appears to have the ability to form intracellularly RNA hybrid duplexes with mRNA. The data presented in this study support the hypothesis that the phenotypic effect of conversion to rough-type LPS is accompanied by the expression of an antisense RNA of phage Acm1.
携带原噬菌体Acm1的溶源性甲醇醋杆菌菌株被发现无法合成荚膜多糖（CPS）和脂多糖（LPS）的O-特异性侧链，并且代表宿主细菌的粗糙变体。噬菌体Acm1的一个262 bp DNA片段，显然是干扰LPS生物合成所必需的，被克隆并在大肠杆菌中表达。无论O型如何，用重组DNA转化各种大肠杆菌菌株都会导致O-特异性链生物合成的抑制。噬菌体Acm1的DNA片段包含三个非常短的开放阅读框，分别为21、24和36 bp。然而，表达噬菌体编码肽的尝试并不成功。相反，源自Acm1的DNA片段被证明编码一种97个核苷酸的反式作用RNA分子，命名为lbi（LPS生物合成干扰）RNA。这种RNA与大肠杆菌靶RNA序列具有序列互补性，并且似乎有能力在细胞内与mRNA形成RNA杂交双链体。本研究提供的数据支持这样的假设，即转化为粗糙型LPS的表型效应伴随着噬菌体Acm1反义RNA的表达。
