Rd. Fu et G. Voordouw, ISD1, AN INSERTION ELEMENT FROM THE SULFATE-REDUCING BACTERIUM DESULFOVIBRIO-VULGARIS HILDENBOROUGH - STRUCTURE, TRANSPOSITION, AND DISTRIBUTION, Applied and environmental microbiology, 64(1), 1998, pp. 53-61
Insertion element ISD1, discovered when its transposition caused the i
nsertional inactivation of an introduced sacB gene, is present in two
copies in the genome of Desulfovibrio vulgaris Hildenborough. Southern
blot analysis indicated at least two insertion sites in the sacB gene
, Cloning and sequencing of a transposed copy of ISD1 indicated a leng
th of 1,200 bp with a pair of 44-bp imperfect inverted repeats at the
ends, flanked by a direct repeat of the 4-bp target sequence, AAGG and
AATT were found to function as target sequences, ISD1 encodes a trans
posase from two overlapping open reading frames by programmed translat
ional frameshifting at an A(6)G shifty codon motif, Sequence compariso
n showed that ISD1 belongs to the IS3 family, Isolation and analysis o
f the chromosomal copies, ISD1-A and ISD1-B, by PCR and sequencing ind
icated that these are not banked by direct repeats, ISD1-A is inserted
in a region of the chromosome containing the gapdh-pgk genes (encodin
g glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase
), Active transposition to other loci in the genome was demonstrated,
offering the potential of a new tool for gene cloning and mutagenesis,
ISD1 is the first transposable element described for the sulfate redu
cers, a large and environmentally important group of bacteria, The dis
tribution of ISD1 in genomes of sulfate-reducing bacteria is limited,
A single copy is present in the genome of D. desulfuricans Norway.