Monoclonal antibodies distinguish titins from heart and skeletal muscle.

Abstract

Abstract. Murine monoclonal antibodies specific for titin have been elicited using a chicken heart muscle residue as antigen. The three antibodies T 1, T3, and T4 recognize both bands of the titin doublet in immunoblot analysis on polypeptides from chicken breast muscle. In contrast, on chicken cardiac myofibrils two of the antibodies (T 1, T4) react only with the upper band of the doublet indicating immunological differences between heart and skeletal muscle titin. This difference is even more pronounced for rat and mouse. Although all three antibodies react with skeletal muscle titin, T 1 and T4 did not detect heart titin, whereas T3 reacts with this titin both in immunofluorescence microscopy and in immunoblots. Immunofluorescence microscopy of myofibrils and frozen tissues from a variety of vertebrates extends these results and shows that the three antibodies recognize different epitopes. All three titin antibodies decorate at the A

The physiological role of titin in striated muscle

“…In addition, flexible, string-like structures morphologically similar to isolated titin were found located at the ends and alongside isolated native thick filaments [85,86]. Binding of anti-titin antibodies confirmed that these structures were titin filaments [9,25].…”

“…On the basis of variations in electrophoretic mobility [1,11,12,26,32,49,89,95, 100] and antibody reactivity [25], several investigators have demonstrated that different striated muscles of an animal can contain different isoforms of titin. Developmental changes in titin isoforms have also been documented [16,107].…”

Nebulin and titin expression in Duchenne muscular dystrophy appears normal

“…Electro° phoresis was performed on linear polyacrylamide gradient gels (2-12% acrylamide; 0.5% crosslinker) in the standard buffer system but omitting a stacking gel. Immunoblotting using hybridoma supernatants was as described [7]. Indirect immunofluorescence microscopy on frozen muscle sections was performed after acetone fixation by standard procedures using the hybridoma supernatants and FITC-labeled sheep anti-mouse antibodies.…”

“…After digestion with restriction enzymes the samples of genomic DNA were electrophoresed on 0.8% agarose, blotted and hybridized to 32p-labeled probes as in [9]. The probes used were kindly provided by Dr P. Pearson (754) [7]). (d-h) Nebulin: (d) normal human skeletal muscle, Nb6, (e) case I, Nb4, (f) case I, Nbl, (g) case Ill, Nb4, (h) case III, Nbl (cross-section).…”

“…In the course of a study on the elastic component of the sarcomer begun 2 years ago [7] we have generated sets of monoclonal antibodies specific for either titin or nebulin from chicken. Immunoelectron-microscopical data to be reported elsewhere showed that the different antibodies in each set recognize different epitopes and that these epitopes are also present in human skeletal muscle (D.F., M.O., R.N.…”