Figure 6.

Ethanol and Ro 25–6981 induce exon usage in Grin1 that may affect NMDAR activity. (A) DEXSeq graph of exon usage for the NMDAR1 gene, Grin1, showing each ensemble exon ID. Corresponding Grin1 transcript with gene locations is displayed below graph where lines indicate introns and grey bars indicate exons. Dotted lines indicate saline- (blue), ethanol- (ETOH; dark grey), or Ro 25–6981- (light grey) induced exon usage. Significant differences from the saline group are indicated by asterisks (*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001). (B) NMDAR1 (white) /NMDAR2B (grey) heterotetramer (left side) and NMDAR1 monomer (right side). Peptides encoded by exons 4, 5, 6, and 8 are indicated in red. Domains are represented by the backdrop color, including the amino-terminal domain (ATD, green), ligand binding domain (LBD, yellow), and transmembrane domain (TMD, blue; PDB ID: 4PE5). (C) Alignment of ATD domains of the unbound structure model apo (white/red; PDB ID: 5B3J) and ifenprodil-bound (grey, PDB ID: 3QEL) structures. Exons 4, 5, 6, and 8 are indicated in red. The ATD has a bi-lobed structure and contains two subdomains, indicated as R1 (top) and R2 (bottom). Three “hinge” loops separating these domains are also shown. Exon numbers represent only the first 8 of 20 exons present along the Grin1 gene that encompass the ATD coding region (Note: panel c is a recreation of a figure previously published; see Figure 1c in Tajima et al., 2016)(Tajima et al., 2016). Subdomain R2 undergoes a 5° rotation from the open to closed conformation. Secondary structure was simplified to clarify the conformational change. (D) Representation of the ATD portion of the NMDAR subunit GluN1 (PDB ID: 4PE5) with peptides encoding DEEs shown in red and clinically observed point mutations shown as yellow spheres. Point mutations occurring in and outside of the DEEs are shown in red and black, respectively. Gold stars in the exon diagram indicate the approximate location of the point mutations.