The Motif Orientation Matters: Structural Determinants of TEAD1 Recognition of Genomic DNA

Transcription enhancer activator domain (TEAD) transcription factors mediate gene expression regulation through interactions with M-CAT motif. They play an important role during development of nearly all eukaryotic organisms and control expression of multiple genes involved in cell proliferation, differentiation or apoptosis. Moreover, activity of TEAD transcription factors is deregulated in several types of cancers. To study the interaction of TEAD1 with M-CAT motifs originating from regulatory regions of human genes (CTGF, SRF, C-MYC and GLUT1), the dissociation constant of each complex was determined by using fluorescence anisotropy assays. Structural mass spectrometry techniques, molecular docking and single-molecule Forster resonance energy transfer enabled structural characterization of these complexes. Chromatin immunoprecipitation and quantitative PCR analysis validated our in-vitro results. The data also indicate that the affinity of TEAD1-DBD for cognate DNA strongly depends on the orientation of the M-CAT motif. Although, the protein-DNA interaction interface is similar when M-CATs are oriented in either the 5’-CCTTA-3’ or 5’-ATTCC-3’ direction, the former leads to approximately 10× higher affinity. Additionally, the 5’-CCTTA-3’ orientation produced a lower TEAD1 occupancy in Jurkat cells, thus suggesting that the low-affinity binding sites present in the human genome may possess biological relevance which is likely associated with its transcriptional regulation.