GENETIC-ANALYSIS OF THE HISTIDINE OPERON CONTROL REGION OF SALMONELLA-TYPHIMURIUM
GENETIC-ANALYSIS OF THE HISTIDINE OPERON CONTROL REGION OF SALMONELLA-TYPHIMURIUM
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DOI：
10.1016/0022-2836(81)90311-9
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发表时间：
1981-01-01
影响因子：
5.6
通讯作者：
ROTH, JR
中科院分区：
文献类型：
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作者：
JOHNSTON, HM;ROTH, JR
组氨酸操纵子控制区 (hisO) 的突变体包括 2 类：完全无法表达操纵子的突变体（His 营养缺陷型）和无法达到完全诱导的操纵子表达水平的原养型突变体（仍然是 His+，但对药物氨基三唑敏感）。新的和以前存在的 hisO 突变体被用来构建 hisO 的精细结构缺失图。突变可能会改变 hisO 1 端的 his 启动子图谱；改变 hisO 另一端 his 衰减器图谱的突变。在启动子和弱化子之间有许多突变，这些突变影响其前导肽基因的翻译或其前导mRNA结构的形成和稳定性。映射到该中心区域的所有点突变以非常高的频率（10-5 至 10-6）恢复为 His+：该频率通过碱基替换和移码诱导诱变剂而增加。许多 His- 突变体被信息抑制子抑制：所有 3 种类型的无义突变都被鉴定出来，这表明启动子和衰减子之间的 hisO 区域的翻译对于 his 操纵子的表达至关重要。所有测试的 hisO 突变均为顺式显性突变。
Mutants of the histidine operon control region (hisO) include 2 classes: those completely unable to express the operon (His auxotrophs) and prototrophs that are unable to achieve fully induced levels of operon expression (still His+ but sensitive to the drug aminotriazole). New and previously existing hisO mutants were used to construct a fine-structure deletion map of hisO. Mutations that presumably alter the his promoter map at 1 end of hisO; mutations that alter the his attenuator map at the other end of hisO. Between the promoter and the attenuator lie a number of mutations that affect the translation of the his leader peptide gene or the formation and stability of his leader mRNA structures. All of the point mutations mapping in this central region revert to His+ at a very high frequency (10-5 to 10-6): this frequency is increased by base substitution and frameshift-inducing mutagens. Many of the His- mutants are suppressed by informational suppressors: all 3 types of nonsense mutations were identified, demonstrating that translation of a region of hisO between the promoter and attenuator is essential for his operon expression. All of the hisO mutations tested are cis-dominant.