Isolation of Sequences Flanking Ac Insertion Sites by Ac Casting

Localizing Ac insertions is a fundamental task in studying Ac -induced mutation and chromosomal rearrangements involving Ac elements. Researchers may sometimes be faced with the situation in which the sequence flanking one side of an Ac /Ds element is known, but the other flank is unknown. Or, a researcher may have a small sequence surrounding the Ac /Ds insertion site and needs to obtain additional flanking genomic sequences. One way to rapidly clone unknown Ac /Ds flanking sequences is via a PCR-based method termed Ac casting. This approach utilizes the somatic transposition activity of Ac during plant development, and provides an efficient means for short-range genome walking. Here we describe the principle of Ac casting, and show how it can be applied to isolate Ac macrotransposon insertion sites.