Abstract

A new insertion sequence, IS14999, from Corynebacterium glutamicum. Microbiology 151: 501-508. 2005. Y. Tsuge, K. Ninomiya, N. Suzuki, M. Inui and H. Yukawa.

A new insertion sequence from Corynebacterium glutamicum ATCC14999 was isolated and characterized. This IS element, designatedIS14999, comprised a 1149 bp nucleotide sequence with 22 bpimperfect terminal inverted repeats. IS14999 carries a singleopen reading frame of 345 amino acids encoding a putativetransposase that appears to have partial homology to IS642,an IS630/Tc1 superfamily element, at the C-terminal region inthe amino acid sequence. This indicated that IS14999 belongedto the IS630/Tc1 superfamily, which was first identified inC. glutamicum. IS14999 has a unique distance of 38 aminoacid residues between the second and third amino acids in theDDE motif, which is well known as the catalytic centre of transposase.This suggested that IS14999 constituted a new subfamily of theIS630/Tc1 superfamily. A phylogenetic tree constructed on thebasis of amino acid sequences of transposases revealed thatthis new transposable element was more similar to eukaryoticTc1/mariner family elements than to prokaryotic IS630 familyelements. Added to the fact that IS14999 was present in onlya few C. glutamicum strains, this implies that IS14999 was probablyacquired by a recent lateral transfer event from eukaryoticcells. Analysis of the insertion site in C. glutamicum R revealedthat IS14999 appeared to transpose at random and always causeda target duplication of a 5'-TA-3' dinucleotide upon insertion,like the other IS630/Tc1 family elements. These findings indicatedthat IS14999 could be a powerful tool for genetic manipulationof corynebacteria and related species.

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