Disease relevance of ISRm3

• Nucleotide sequence analysis revealed that IS6120 contains two open reading frames, one of which encodes a putative transposase with similarities to those found in IS256 from Staphylococcus aureus, IST2 from Thiobacillus ferrooxidans, and ISRm3 from Rhizobium meliloti [1].
• Comparison of the putative protein encoded with sequences derived from the EMBL and GenBank databases showed significant similarity between the putative transposases of ISRm3 from R. meliloti, IS256 from Staphylococcus aureus, and IST2 from Thiobacillus ferroxidans [2].
• IS1166 and IS1295 are new members of a family of IS elements which includes IS6120 from Mycobacterium smegmatis, IST2 from Thiobacillus ferrooxidans, IS256 from Staphylococcus aureus and ISRm3 from Rhizobium meliloti [3].
• It carries a single open reading frame encoding a 369-amino-acid protein, which shares homology with transposases found in a class of related IS, including ISRm3 from Rhizobium meliloti, IS256 from Staphylococcus aureus, IS6120 from Mycobacterium smegmatis, IS1081 from M. bovis, IST2 from Thiobacillus ferroxidans and IS406 from Pseudomonas cepacia [4].

High impact information on ISRm3

• An open reading frame that spans 89% of the length of one DNA strand encodes a putative transposase with significant similarity to the putative transposases of 11 insertion sequence elements from diverse bacterial species, including ISRm3 from R. meliloti [5].
• Multiple copies and variants of ISRm5 occur in the R. meliloti genome, often in close association with ISRm3 [5].
• Nucleotide sequence of Rhizobium meliloti GR4 insertion sequence ISRm3 linked to the nodulation competitiveness locus nfe [6].
• Upon examination of the extended DNA region containing host-specific nodulation genes nodFEG and nodH, we found that the nodG gene of WL131 bears a novel insertion sequence, ISRm3 [7].
• Analysis of six copies of ISRm3 in two strains showed that a variable number of base pairs (usually eight or nine) were duplicated and formed direct repeats adjacent to the site of insertion [2].

Biological context of ISRm3

• The entire nucleotide sequence of ISRm3 in R. meliloti 102F70 is 1,298 bp and has 30-bp terminal inverted repeats which are perfectly matched [2].
• This plasmid is indigenous to strain IZ450 and fortuitously contained four copies of ISRm3 [2].

Analytical, diagnostic and therapeutic context of ISRm3

• Genomic DNA fingerprinting with insertion elements ISRm3 and ISRm2011-2 suggested that transposition of these elements was not a cause of variation, but a DNA band was absent in the profiles of two out of three W2-like colonies [8].

References