Abstract
The ASYMMETRIC LEAVES1 (AS1) and AS2 genes of Arabidopsis thaliana regulate formation of a symmetrical, expanded lamina. AS1 and AS2 are thought to act as a transcriptional regulator of certain genes including class 1 KNOX genes. To identify genes regulated by AS1 and AS2, we performed DNA microarray and clustering analysis by Knowledge-based Fuzzy Adaptive Resonance Theory. We found that AS1 and AS2 repressed abaxial determinants, ETT, KAN2 and YAB5 in addition to class 1 KNOX genes. To know how AS1 and AS2 regulate these genes, we performed ChIP assay and chip-on chip analysis. Our results suggested that AS1 may directly regulate ETT by binding to ETT promoter region. Our genetic analysis of AS1, AS2, ETT, and ARF4 suggested that AS1 and AS2 repress the expression of both ETT and ARF4, which are closely related members of ARF family, and known to be targets of tasiR-ARF. We will discuss the significance of repression of the ETT gene directly and the ARF4 gene indirectly by AS1 and AS2 for the establishment of adxial-abaxial and medio-lateral polarity of leaves in Arabidopsis thaliana.
