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Structure of two retrons of Escherichia coli and their common chromosomal insertion site
Author(s) -
Lim D.
Publication year - 1991
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1991.tb00810.x
Subject(s) - biology , genetics , escherichia coli , gene , insertion sequence , open reading frame , rna , direct repeat , nucleic acid sequence , dna , microbiology and biotechnology , transposable element , peptide sequence , mutant , genome
Summary It has been shown that certain strains of myxobacteria and of Escherichia coli have a genetic element encoding a reverse transcriptase (RT). This element, called a ‘retron’, produces a covalently linked RNA–DNA compound (msDNA–RNA). Here, I report the complete nucleotide sequence of retron EC‐86, the retron in E. coli B, together with its flanking regions. Retron EC‐86 contains genes for msDNA–RNA ( msd , and msr ), a gene for RT ( ret ) and a gene for an open reading frame whose function is unknown. The upstream junction is composed of the sequence GCGCGCGC, but there are no direct or inverted repeats at the retron–host junctions. It is also shown that another retron of E. coli , EC‐67, which was isolated originally from the clinical strain CL1 and was later found to be present also in a clinical E. coli isolate from Brazil, is inserted at the same chromosomal site as retron EC‐66. Retron EC‐67 contains only msd, msr , and ret. I suggest that these two retrons were independently inserted into the same site of their host strains via a novel mechanism of integration.