Abstract
ASYMMETRIC LEAVES1 (AS1) and AS2 are involved in the axes-dependent leaf development in Arabidopsis. AS1 and AS2 proteins contain Myb- and AS2/LOB-domains, respectively. These proteins interact each other in vitro. However, the interaction in vivo remains elusive, since the accumulation patterns of each transcripts are not same. To assess it, we attempted to narrow down the regions of AS1 and AS2 proteins for the interaction. And the results were that the essential region of AS1 for the interaction with AS2 was not found and that the essential region of AS2 for the specific interaction with AS1 roughly agreed with the conserved AS2/LOB-domain. We also found the single amino acid replacements, which confer the deficiency in the interaction with AS1, in the essential region. One of them, the LP mutant failed to reverse the phenotype of as2 mutant plants. However, the artificial fusion protein of AS2 and AS1 carrying the LP mutation could reverse and overcome the phenotype. These results suggest that the LP mutant AS2 still has the functions other than the interaction with AS1 and that the interaction with AS1 is essential for the function of AS2 protein.
