Fig. 3

Overview over PGC-1α isoforms in murine heart (passed QC). PGC-1α isoforms (mRNA) after SMRT sequencing which passed QC filtering (Fig. 1): Differing starting exons 1a, b, b’ or c (blue boxes), canonical main exons (orange boxes), novel/altered exons (red boxes) and functional domains (green boxes, details see text). Length of boxes indicates relative length of nucleotides (true to scale, with exception of exon 8: shortened bp marked), asterisks and red background layer indicating novel isoforms. A Isoforms consisting of either exon 1a, b, b’ or the novel exon 1c followed by only canonical main exons. B Isoforms starting with exon 1a or b followed by canonical exon 2 to exon 12 and then followed by a novel exon 13b and novel exon 14 (new C-terminal end). C Isoforms with starting exon 1a or b and novel exon 6b, ending in the canonical C-terminal end (two isoforms) or with a novel exon 13c (one isoform). D N-terminal isoforms (known), with either starting with exon 1a, b or b’ and ending preliminary due to an alternative exon 7b. E Novel N-terminal isoform, shorter than the known (see D; therefore prefixed with ‘s’), ending in a novel exon 3b / exon 4b. This isoform is the shortest isoform in the overall pattern. F Novel isoform group consisting of different splicing events upstream exon 3, resulting in a shift of the start codon inside exon 3 with valid open reading frame. Three variants exist, differing in the 5′-end (either canonical C-, novel C- or N-terminal end)