COMPARATIVE-ANALYSIS OF NONRANDOM DNA-REPAIR FOLLOWING AC TRANSPOSON EXCISION IN MAIZE AND ARABIDOPSIS

Ac/Ds transposable elements often leave short DNA rearrangements, or ' footprints,' at the sites where they excise. Previous studies at the m aize waxy (wx) gene suggest that the DNA repair that forms transposon footprints is not random. Each excision site consistently displays a d ifferent, predominant repair product suggesting flanking DNA may influ ence footprint formation. We have expanded these studies to show that predominant end-joining products also form in association with Ac/Ds e xcision in Arabidopsis and that chromosomal location of the Ac-contain ing construct does not appear to influence this repair. The predominan t repair product is identical in both maize and Arabidopsis for Ac ele ments with the same adjacent DNA sequences. However, a broader range o f minor footprint types is observed in Arabidopsis, including footprin ts that are rare in maize, suggesting potential differences in the hos t proteins involved in either transposition, repair or both. The data also suggest that the sequences influencing footprint formation are wi thin 39 bp 5' and 18 bp 3' of the transposon. These studies demonstrat e that transgenic Ac/Ds-containing plants will be useful tools in diss ecting plant DNA repair processes.