Open AccessIron mediated methylthiolation of tRNA as a regulator of operon expression inEscherichia coli
Author(s) -
Martin Buck,
Elwyn Griffiths
Publication year - 1982
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/10.8.2609
Subject(s) - operon , biology , transfer rna , transcription (linguistics) , escherichia coli , translation (biology) , polynucleotide , mutant , rna , genetics , trp operon , messenger rna , biochemistry , gene , microbiology and biotechnology , linguistics , philosophy
E. coli growing in the presence of iron-binding proteins produced tRNAtrp and tRNAphe molecules containing i6A instead of ms2i6A adjacent to the anticodon. These undermodified tRNAs functioned less efficiently than the fully modified molecules when translating synthetic polynucleotides containing contiguous codons in an in vitro system, but did not limit the translation of MS2 RNA. We examined the possibility that the altered tRNAs with lowered translational efficiencies could relieve transcription termination at the trp and phe attenuators and lead to increased operon expression under iron restricted conditions. Using trpR mutants we found that there was indeed greater expression of the trp operon during iron restricted growth. This increase was attributable solely to the tRNA alteration induced by iron restriction.