FIGURE 2.

GR isoforms generated by alternative splicing. The human GR primary transcript is composed of nine exons, with exon 2 encoding most of the NTD, exons 3 and 4 encoding the DBD, and exons 5–9 encoding the hinge region (H) and LBD. The classic GRα protein results from splicing of exon 8 to the beginning of exon 9. GRβ is produced from an alternative splice acceptor site that links the end of exon 8 to downstream sequences in exon 9, encoding a variant with a unique 15-amino acid C terminus (positions 728–742). GRγ is generated by an alternative splice donor site in the intronic sequence separating exons 3 and 4, resulting in a protein with an arginine insertion (Arg-452) between the two zinc fingers of the DBD. GR-A is produced from alternative splicing that joins exon 4 to exon 8, deleting the proximal 185 amino acids of the LBD (Ala-490–Ser-674) encoded by exons 5–7. GR-P is formed by a failure to splice exon 7 to exon 8. The retained intronic sequence introduces a stop codon, resulting in a truncated receptor mutant missing the distal half of the LBD.