A RIBOSOMAL AMBIGUITY MUTATION
A RIBOSOMAL AMBIGUITY MUTATION
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DOI：
10.1016/0022-2836(69)90336-2
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发表时间：
1969-01-01
影响因子：
5.6
通讯作者：
GORINI, L
中科院分区：
文献类型：
--
作者：
ROSSET, R;GORINI, L
已证明存在控制翻译歧义的 30 s 核糖体成分的遗传决定因素。它位于strA（链霉素敏感性）区域，与spc（壮观霉素敏感性）基因99%可共转导。在体外，突变核糖体广泛误读，通过交换ramandram+核糖体的亚基，表明误读是30 s亚基的特性。在体内，热突变赋予细胞抑制所有三个无义密码子的能力。链霉素在体外和体内都会引起类似的普遍模糊表型。链霉素和链霉素的作用是相加的。由链霉素和它们的组合引起的歧义在体内和体外被strA位点的额外突变所拮抗。因此，strA40（有抗性）和strA1（无抗性）等位基因越来越多地限制核糖体（以及tRNA）抑制，并使野生型strA+菌株中突变产生的生长速率降低恢复正常。亚致死剂量的链霉素可完全抑制aram1、strA+菌株的生长，较高剂量的链霉素可完全抑制inram1、strA40菌株的生长，而ram1、strA1菌株对链霉素无影响。该药物的杀菌作用与这些作用无关。
The existence of a genetic determinantram‡for a 30 s ribosomal component controlling translation ambiguity has been demonstrated. It is located in thestrA(streptomycin sensitivity) region and is 99% cotransducible with thespc(spectinomycin sensitivity) gene.In vitro, rammutant ribosomes misread extensively and by interchanging the subunits oframandram+ribosomes it is shown that misreading is a property of the 30 s subunit.In vivo, therammutation confers on the cell the ability to suppress all three nonsense codons. Streptomycin induces a similar generalized ambiguity phenotypically bothin vitroandin vivo. The effects oframand of streptomycin are additive.Ambiguity caused byram, by streptomycin and by their combination is antagonizedin vivoandin vitroby additional mutations at thestrAlocus. Thus thestrA40(resistant competent) andstrA1(resistant incompetent) alleles increasingly restrict ribosomal (as well as tRNA) suppression and return to normal the reduced growth rate produced byrammutation in a wild-typestrA+strain. Growth is inhibited completely in aram1,strA+strain by sublethal doses of streptomycin and inram1,strA40strains by higher doses, while strainram1,strA1is indifferent to streptomycin. The bactericidal action of the drug is unrelated to these effects.