Regulation of flowering in Arabidopsis by an FLC homologue

The Arabidopsis FLC gene encodes a MADS domain protein that acts as a repre ssor of flowering. Late-flowering vernalization-responsive ecotypes and mut ants have high steady-state levels of FLC transcript, which decrease during the promotion of flowering by vernalization. Therefore, FLC has a central role in regulating the response to vernalization. We have isolated an Arabi dopsis gene, MAF1, which encodes a protein that is closely related to FLC. Overexpression studies demonstrate that MAF1 produces comparable effects to FLC, and likely has a similar function in the regulation of flowering. In contrast to FLC, however, MAF1 expression shows a less clear correlation wi th the vernalization response. In addition, MAF1 overexpression does not in fluence FLC transcript levels. Thus, MAF1 likely acts downstream or indepen dently of FLC transcription. We further report identification of a cluster of four additional FLC-like genes in the Arabidopsis genome.