Fig. 6. Tissue distribution of the three alternatively spliced transcripts of FoxK1 in adult T. rubripes. Relative expression levels of TFoxK1- (blue bars), TFoxK1- (yellow bars) or TFoxK1- (red bars) in fast muscle (WM), slow muscle (RM), heart (H), liver (L), skin (SK), brain (B) and gonads (G) are represented as ratios against the expression level of TFoxK1- in fast muscle. RNA polymerase II was used as standard. Values are means ± s.e.m. (N=4). Statistically significant differences (P<0.05) between splice variants within a tissue are labelled with the same letter; significant differences in expression of an isoform across different tissues are indicated by the same number. (Inset) Expression of FoxK1- in fast myotomal muscle of adult fish. Transverse sections of fast muscle were immunostained for FoxK1-, a molecular marker of muscle progenitor cells (MPCs). FoxK1--positive nuclei (indicated by arrowheads) occupy a sublaminar position that is typical of MPCs.