Heterogeneity of chicken slow skeletal muscle troponin T mRNA

The troponin T (TnT) transcripts in chicken slow skeletal muscle were characterized by S1 nuclease mapping and nucleotide sequencing of cDNA produced by RT-PCR and 5'-RACE. We found two kinds of transcripts in the 5'-region, one having the codon for alanine (position 135-137), C (258), and A (262) and the other lacking the codon and having T (258) and G (262) instead of C and A. In the 3'-region, we found four single base substitutions at 703 (T or C), 774 or T), 797 or T), and 827 (G or A). Four of the six substitutions lead to amino acid changes in chicken sTnT isoforms. We determined the genomic structure of the 3'-region of the chicken sTnT gene. The region includes 7 exons corresponding to position 249-891 of the chicken sTnT cDNA and no alternative exon, showing that the 3'-heterogeneity in sTnT transcripts was due to allelic variation. J. Exp. Zool. 286:149-156, 2000.