Abstract
An active transposon in intact plants has been identified in rice. The 607-bp transposon, termed nonautonomous DNA-based active rice transposon (nDart), has no coding capacity and was found in the gene encoding Mg-protoporphyrin IX methyltransferase in a chlorophyll-deficient albino mutant isolated from the backcrossed progeny of the cross between japonica varieties. nDart has 19-bp terminal inverted repeats (TIRs) and generates an 8-bp target-site duplication (TSD). At least, 13 nDart elements were found in the rice genome of Nipponbare. We also found larger elements, termed DNA-based active rice transposon (Dart) , that contained one ORF. Dart shares several features with nDart, including identical TIRs, similar subterminal sequences and the generation of an 8-bp TSD. We conclude that these active transposons in intact rice plant, nDart and Dart, belong to the hAT superfamily of class 2 transposons.
