Figure 1

Alignment of E2A sequences from human, mouse, xenopus and chicken: full-length E12 (A) and the E47 bHLH exon (B) which replaces the E12 bHLH exon in the full-length sequence. "*" denotes identical residues, ":" conserved substitutions as recorded in CLUSTAL, and "." semi-conservative substitutions. Accession numbers for the sequences used are: PI5923, XM125750, X66959 for human, mouse and Xenopus, respectively. The chicken sequence has been assigned the accession number AJ579995 for E12 and AJ579996 for E47. Shaded boxes denote functionally defined regions: activation domain I (ADI) with boxed helix [29], activation domain II (ADII) [17] and the ubiquitin ligase interaction domain [18]. The putative NLS is underlined and the bHLH region is boxed in black. The exon border of the xenopus sequence is based on its homology to the other sequences. Chicken amino acid 221 (bold) is the first aa of the ΔADI constructs used in the functional analysis.