Immunohistochemical studies on regulation of alternative splicing of fast skeletal muscle troponin T: non-uniform distribution of the exon x3 epitope in a single muscle fiber.
Troponin T (TnT) isoforms of chicken fast skeletal muscle are classified into two types, breast-muscle-type (B-type) and leg-muscle-type (L-type) isoforms. These isoforms are produced from a single gene by differential alternative splicing of pre-mRNA. We investigated immunohistochemically the distribution of B-type TnT isoforms in chicken leg muscle (musculus biceps femoris), using anti-exon x3 that was raised against a synthetic peptide corresponding to exon x3 and recognized B-type, but not the L-type, TnT isoforms. Mosaic patterns of immunostaining showing locally different expression of B-type TnT isoforms in a single fiber were observed among fibers, and the non-uniform distribution of the isoforms was also detected in sectioned fibers and myofibrils from the muscle. The results indicated that regulation of pre-mRNA splicing of fast skeletal muscle TnT was different not only among the muscle fibers but also within a single fiber, suggesting that heterogeneous myonuclei in regulation of alternative splicings occur in a single muscle fiber.
Nakada
K
K
Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Kimura
F
F
Hirabayashi
T
T
Miyazaki
J I
JI
D017398:Alternative Splicing / Q000502:physiology*; D000818:Animals; D002645:Chickens; D000939:Epitopes / Q000032:analysis / Q000235:genetics; D005091:Exons / Q000235:genetics*; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation; D005796:Genes; D016253:Microscopy, Immunoelectron; D018656:Muscle Fibers, Fast-Twitch / Q000737:chemistry*; D020033:Protein Isoforms / Q000235:genetics* / Q000276:immunology; D012322:RNA Precursors / Q000235:genetics; D020107:Troponin T / Q000235:genetics* / Q000276:immunology
D000939:Epitopes; D020033:Protein Isoforms; D012322:RNA Precursors; D020107:Troponin T