Identification of multiple variants of fast muscle troponin T in the chicken using monoclonal antibodies.

Two monoclonal antibodies, T1/7 and T1/61, have been prepared which are specific for chicken fast muscle troponin T. Both are of the IgG gamma 1 subclass. Both antibodies cross-react strongly with human fast and chicken cardiac troponin T, but while T1/7 reacts weakly with rabbit fast troponin T, T1/61 does not. The antibodies can be used for fibre typing of both chicken and human muscle. The antibodies have been used to identify fast troponin T on two-dimensional maps of proteins from a variety of chicken muscles by electrophoretic transfer to nitrocellulose followed by immunoperoxidase staining. Using this technique five variant forms of fast troponin T have been identified. Two variants, fBT1 and fBT2, are expressed in breast muscle, while the other three, fLT1, fLT2 and fLT3 are expressed in leg muscle. Of the leg muscle variants, fLT1 and fLT2 correspond to the two forms described previously [Wilkinson, J.M., Moir, A.J.G. and Waterfield, M.D. (1984) Eur. J. Biochem. 143, 47-56]. The third variant, fLT3, has not been described before and is expressed in muscles which have a high content of slow fibres. In addition to these clearly defined variant forms immunostaining reveals multiple minor variants of troponin T present in leg muscle which may reflect complex RNA processing of the troponin T gene transcript.