Lineage specific conservation of cis-regulatory elements in Cytokinin Response Factors

Expression patterns of genes are controlled by short regions of DNA in promoter regions known as cis-regulatory elements. How expression patterns change due to alterations in cis-regulatory elements in the context of gene duplication are not well studied in plants. Over 300 promoter sequences from a small, well-conserved family of plant transcription factors known as Cytokinin Response Factors (CRFs) were examined for conserved motifs across several known clades present in Angiosperms. General CRF and lineage specific motifs were identified. Once identified, significantly enriched motifs were then compared to known transcription factor binding sites to elucidate potential functional roles. Additionally, presence of similar motifs shows that levels of conservation exist between different CRFs across land plants, likely occurring through processes of neo- or sub-functionalization. Furthermore, significant patterns of motif conservation are seen within and between CRF clades suggesting cis-regulatory regions have been conserved throughout CRF evolution.