Abstract
We have developed a new activation tagging system in which Arabidopsis plants expressing a GAL4:VP16 transcription activator in a tissue-specific manner were transformed with a T-DNA that harbors GAL4-binding sequences (UAS). By using this method we isolated eight UAS-tagged root patterning (urp) mutants, urp1D through urp8D. Tagged genes were identified by determining T-DNA insertion sites, followed by co-segregation and recapitulation experiments. Seven of the eight genes were found to encode putative transcription factors belonging to AP2, NAC, C2H2 Zinc finger, R2R3 MYB, DOF and RWP-RK families. Expression studies indicated that at least some of these genes are expressed specifically in certain cell types in the root meristem region. Two of these genes have been implicated in root patterning by other groups through an elaborated marker-based screening or homology-based functional studies, indicating that our method is effective in identifying novel genes that have escaped from conventional mutant screenings.
