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Figure 14 | BMC Evolutionary Biology

Figure 14

From: Structural diversity and evolution of the N-terminal isoform-specific region of ecdysone receptor-A and -B1 isoforms in insects

Figure 14

Hypothetical model of the B1 isoform-specific region mediated transcriptional regulation. (A) Sequence comparison between two acidic activator domains of herpes virus protein VP16 and the consensus sequences of the DL-rich motif of the EcR-B1 isoform. Two acidic activation domains of VP16 (GenBank accession number; NP_044650) were aligned with the consensus sequences of the DL-rich motifs of the type 1-5 B1 isoform-specific regions. The DL-rich motif of EcR-B1 isoform and the VP16 acidic activation domains comprise tandem repeats of acidic residues and aromatic/bulky hydrophobic residues. The amino acid residues are represented in the default color scheme of ClustalX. Asterisks indicate identical residues and colons indicate similar residues. (B) Schematic model of the action of the EcR-B1 isoform-specific AF-1. The S-rich and DL-rich motifs might interact with co-regulatory proteins essential for B1 isoform-specific AF-1. The holometabolous insect EcR-B1 isoform might have acquired a novel interaction partner(s) in the holometabolous insect-specific (K/R)RRW motif.

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