UC San Diego
Insights into the regulation of apical fate in Arabidopsis thaliana embryogenesis
- Author(s): Hannon, Michael J.
- et al.
Development of the shoot and root meristems occurs during embryogenesis. The establishment and maintenance of these key tissue types is regulated both by the phytohormone auxin and the putative transcriptional co-repressor TOPLESS (TPL) and its family members. Here we show physical interaction between TPL and the auxin response repressor an AUX/IAA, IAA12 and present genetic evidence that supports TPL's role as a transcriptional co- repressor. In addition we show that both TPL and IAA12 can function as repressors in an in planta repressor assay. Finally, using the tpl-1 allele which shows temperature sensitive, dominant negative activity for TPL and its family members, we identify and provide the initial characterization of a new player in the maintenance of the shoot apical meristem. This gene, POLAR BARE (PBR), encodes a putative serine carboxypeptidase that is expressed in the protoderm and the upper layers (L1 and L2) of the developing shoot apical meristem during embryogenesis. We pspeculate that this protein may be involved in small peptide signaling that regulates apical fate, which could lead to new insights about apical polarity