Fig. 4

DLG2 gene model and exon mapping in mouse and human. a Qualitative graphical representation of H3K4me3 peak (HP), upstream promoter, and coding first exon (CFE). TSS transcription start site. b Two DLG2 gene models using UCSC data: the hg19/hg38 model at the top and the new model integrating our research regarding two novel promoters and coding first exons (CFEin7 and CFEin8) at the bottom. c mm9/mm10 and new Dlg2 models comparison. d DLG2/Dlg2 exon mapping by DNA sequence alignment. Bidirectional arrows between exons represent the best match according to NCBI BLAST. Arrows with tips pointing leftwards show transcription start sites according to UCSC, updated with our results. Bold annotations, such as “h3” and “m8”, mark the beginning of protein isoforms according to UniProtKB/Swiss-Prot, in human (Q15700) and mouse (Q91XM9). Regarding the mouse isoform terminology, “mX” stands for Q91XM9-X and m1, 2, 3, 4, 6, and 7 correspond, respectively, to PSD93-alpha, beta, gamma, delta, epsilon, and zeta. Human exons 3–6 and 10 are annotated with an asterisk because there is evidence (see “Methods” and Additional file 1: Supplementary note 10) that they map to unannotated Dlg2 mouse exons in mm10 reference genomes. Those “missing” murine exons code for “m3” and “m7” protein isoforms, and are depicted with dashed borders. “m5” represents DLG2 isoform “Q91XM9-5” and maps from mouse exon 3 to exon 11 (Additional file 1: Supplementary note 4). It is not included in the figure because no experimental confirmation of its existence is available. In UniProt, “h5” is also reported as not experimentally proven. However, in GTEx (adult brain), it is the most expressed isoform (see ENST00000426717 in Additional file 1: Figure S26). Hence, it is included in the figure