Fig. 3. Identification of troponin I (TnI) and troponin C (TnC) isoforms in the various R. pipiens fibre types. (Left) SDS-PAGE (silver stained) banding pattern of single skinned fibres representing most of the different fibre types. All fibres (fibre types labeled at bottom of gel lanes) were obtained from one frog and were typed by MHC banding pattern after SDS-PAGE as in Fig. 1 (not shown). (Right) Western blots of the gel on left using anti-TnI and anti-TnC antibodies. Anti-TnI labeled one isoform in fast twitch fibres (TnIf) and a unique isoform in tonic fibres (TnIT). Anti-TnC labeled an isoform in tonic fibres (TnCT) that was not expressed in any other fibre type, but did not react with the TnC isoform present in fast twitch fibres (TnCf). The position of TnCf was deduced from indirect evidence (see Results for details). The lightly stained band below MLC2f in twitch fibres is an unidentified contaminant that is not typically present (see Figs 1, 2 and 4). Note, this frog did not contain the MLC1x isoform in any of its fibres.
