Regulation of the floral repressor gene FLC: the complexity of transcription in a chromatin context

The genetic pathways regulating the floral transition in Arabidopsis are becoming increasingly well understood. The ease with which mutant phenotypes can be quantified has led to many suppressor screens and the molecular identification of the underlying genes. One focus has been on the pathways that regulate the gene encoding the floral repressor FLC. This has revealed a set of antagonistic pathways comprising evolutionary conserved activities that link chromatin regulation, transcription level and co-transcriptional RNA metabolism. Here we discuss our current understanding of the transcriptional activation of FLC, how different activities are integrated at this one locus and why FLC regulation seems so sensitive to mutation in these conserved gene regulatory pathways.

Research highlights▶ The floral repressor FLC is the target of several regulatory pathways. ▶ Conserved chromatin complexes are required for transcriptional activation of FLC. ▶ A putative FRIGIDA complex is required for FLC activation. ▶ FLC expression is reactivated during the late reproductive phase.