Locating Transcription Activation Activity in Dlx5 and Dlx6 Proteins
Dlx genes are important for vertebrate embryogenesis, encoding transcriptions factors that typically activate downstream targets. Dlx5 and Dlx6 mutants have defects in the mandible. However, Dlx5 and Dlx6 double knockout mutants show complete transformation of the mandibular arch, supporting the claim that Dlx5 and Dlx6 are functionally redundant. The amino- and carboxy-terminal domains of Dlx proteins are predicted to be intrinsically disordered; short linear motifs, that are critical for transcription activity, have been identified in the disordered regions of transcription factors. Such motifs within Dlx proteins that are important for transcription activity remain to be discovered. A truncation strategy was used to locate important residues in Dlx5 and Dlx6 proteins for transcription function. The data indicate that both Dlx5 and Dlx6 contain functionally redundant activation activities, and that the strength of the activation function is proportional to the length of each domain, rather than being located in a specific motif.