Type-3 B1 isoform-specific region. The type-4 B1 isoform-specific region contained four conserved microdomains. (A) Schematic representation of the type-4 B1 isoform-specific regions. Positions of the (K/R)RRW motif, the S-rich motif, the SP residues, and the DL-rich motif are indicated by colored boxes. (B) The alignment and Sequence Logo representation of the conserved microdomains of the type-4 B1 isoform-specific region. The amino acid residues are represented in the default color scheme of ClustalX. Asterisks indicate identical residues and colons indicate similar residues.