Heatmap of transcription factor binding affinities for all identified miRNA promoters. All identified miRNA promoters are clustered based on their affinity profiles for the 130 JASPAR core vertebrate factors. Cluster 3 is enriched in intronic promoters, while cluster 1 is enriched in host gene promoters. The transcription factors highlighted in the box on the right side are those with a high affinity for intronic promoters, which are also identified as significantly enriched by TRAP. The transcription factors in the box on the left side are those with a high affinity for host gene promoters, also reported by TRAP as significantly enriched in the same promoter class.