GENE IN THE MAJOR CO-TRANSDUCTION GAP OF THE ESCHERICHIA-COLI K-12 LINKAGE MAP REQUIRED FOR THE EXPRESSION OF CHROMOSOMAL RESISTANCE TO TETRACYCLINE AND OTHER ANTIBIOTICS
GENE IN THE MAJOR CO-TRANSDUCTION GAP OF THE ESCHERICHIA-COLI K-12 LINKAGE MAP REQUIRED FOR THE EXPRESSION OF CHROMOSOMAL RESISTANCE TO TETRACYCLINE AND OTHER ANTIBIOTICS
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DOI：
10.1128/jb.155.2.541-548.1983
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发表时间：
1983-01-01
影响因子：
3.2
通讯作者：
LEVY, SB
中科院分区：
文献类型：
--
作者：
GEORGE, AM;LEVY, SB
在大肠大肠杆菌K-12对四环素、氯霉素及其他无关抗生素的耐药性至少由4个空间上分离的位点介导。四环素敏感的突变体分离Tn 5插入失活的扩增的多重耐药菌株。其中之一，详细研究，显示所有其他抗性表型的表达的协调损失。该突变体中的Tn 5元件定位在E. coliK-12连锁图谱。该基因座被命名为marA（多重抗生素抗性）。四环素敏感的突变体含有marA：：Tn 5恢复所有的耐药表型的频率为10-8至10-7精确切除Tn 5。一种新描述的四环素外排系统在四环素敏感突变体中失活，但在四环素抗性回复突变体中恢复。在部分二倍体中，F-prime marA+对相应的突变体染色体等位基因表现部分或完全显性。显性试验还表明，先前扩增的宿主和突变的marA等位基因是表型抗性表达的先决条件。
In E. coli K-12, amplifiable resistance to tetracycline, chloramphenicol and other unrelated antibiotics was mediated by at least 4 spatially separated loci. Tetracycline-sensitive mutants were isolated by Tn5 insertional inactivation of an amplified multiply resistant strain. One of these, studied in detail, showed coordinate loss of expression of all other resistance phenotypes. The Tn5 element in this mutant mapped to 34 min on the E. coli K-12 linkage map. The locus was designated marA (multiple antibiotic resistance). Tetracycline-sensitive mutants containing marA::Tn5 regained all resistance phenotypes at frequencies of 10-8 to 10-7 upon precise excision of Tn5. A newly described tetracycline efflux system was inactivated in tetracycline-sensitive mutants, but recovered in tetracycline-resistant revertants. In merodiploids, F-prime marA+ expressed partial or complete dominance over corresponding mutant chromosomal alleles. Dominance tests also established that a previously amplified host and a mutant marA allele were preconditions for the expression of phenotypic resistances.