A FUSION PROMOTER CREATED BY A NEW INSERTION-SEQUENCE, IS1490, ACTIVATES TRANSCRIPTION OF 2,4,5-TRICHLOROPHENOXYACETIC ACID CATABOLIC GENESIN BURKHOLDERIA-CEPACIA AC1100
A. Hubner et W. Hendrickson, A FUSION PROMOTER CREATED BY A NEW INSERTION-SEQUENCE, IS1490, ACTIVATES TRANSCRIPTION OF 2,4,5-TRICHLOROPHENOXYACETIC ACID CATABOLIC GENESIN BURKHOLDERIA-CEPACIA AC1100, Journal of bacteriology, 179(8), 1997, pp. 2717-2723
Transposition and transcriptional activation by insertion sequences in
Burkholderia cepacia AC1100 were investigated, Two closely related ne
w elements, IS1413 and IS1490, were identified and characterized, Thes
e elements are not highly related to other insertion sequences identif
ied in AC1100 or other B. cepacia isolates, Based on their structures
and the sequences of the inverted terminal repeats and the putative tr
ansposase protein, the insertion elements (IS elements) are similar to
IST2 of Thiobacillus ferrooxidans and several related elements, All t
he IS elements that have been identified in this strain are found in m
ultiple copies (10 to 40), and they have high-level promoter activity
capable of stimulating transcription from a distance up to 500 bp from
a target gene, Strain AC1100 was originally isolated after prolonged
selection for the ability to utilize the herbicide 2,4,5-trichlorophen
oxyacetic acid (2,4,5-T) as a sole carbon source, Three IS elements ar
e located near the first gene of the 2,4,5-T catabolic pathway, tftA.
IS1490 inserted 110 bp upstream of tfrA and created a fusion promoter
responsible for constitutive transcription of the gene, Our results co
nfirm the hypothesis that IS elements play a central role in transcrip
tion of 2,4,5-T genes and likely have stimulated rapid evolution of th
e metabolic pathway.