Generation of new transposons in vivo: an evolutionary role for the "staggered" head-to-head dimer and one-ended transposition.
From a plasmid carrying the tnpA gene and one inverted repeat sequence (IR) of transposon Tn3, plasmids containing a structure characteristic of transposons, i.e., two IRs flanking a tnpA gene, were generated spontaneously in vivo. They appear to have arisen either through the formation of a "staggered" head-to-head dimer or by so-called one-ended transposition. These putative transposons could indeed transpose to, or form cointegrates with, a recipient plasmid. Based on these findings it is proposed that a primeval transposase gene and its target site evolved first, and subsequently gave rise to a "fully-fledged" transposon by head-to-head dimerization or one-ended transposition.
Morita
M
M
Laboratory of Molecular Biology, Kansai Medical University, Hirakata, Osaka, Japan.
Umemoto
A
A
Watanabe
H
H
Nakazono
N
N
Sugino
Y
Y
D001483:Base Sequence; D004251:DNA Transposable Elements; D004274:DNA, Recombinant; D004268:DNA-Binding Proteins / Q000235:genetics; D019281:Dimerization; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics
D004251:DNA Transposable Elements; D004274:DNA, Recombinant; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D012097:Repressor Proteins