No abstract

The mechanisms for the regulation of homeotic genes are poorly understood in most organisms, including plants. We identified BASIC PENTACYSTEINE1 (BPC1) as a regulator of the homeotic Arabidopsis thaliana gene SEEDSTICK (STK), which controls ovule identity, and characterized its mechanism of action. A combination of tethered particle motion analysis and electromobility shift assays revealed that BPC1 is able to induce conformational changes by cooperative binding to purine-rich elements present in the STK regulatory sequence. Analysis of STK expression in the bpc1 mutant showed that STK is upregulated. Our results give insight into the regulation of gene expression in plants and provide the basis for further studies to understand the mechanisms that control ovule identity in Arabidopsis.

Flower development is a key process for all angiosperms and is essential for sexual reproduction. The last phase in flower development is fertilization of the ovules and formation of the fruits, which are both biologically and economically of importance. Here, we report the expression profiles of over 1100 unique Arabidopsis genes coding for known and putative transcription factors (TFs) during silique development using high-density filter array hybridizations. Hierarchical cluster analyses revealed distinct expression profiles for the different silique developmental stages. This allowed a functional classification of these expression profiles in groups, namely pistil development, embryogenesis, seed maturation, fruit maturation, and fruit development. A further focus was made on the MADS-box family, which contains many members that are functionally well-characterized. The expression profiles of these MADS-box genes during silique development give additional clues on their functions and evolutionary relationship.

No abstract