HUMAN CARDIAC TROPONIN-T - IDENTIFICATION OF FETAL ISOFORMS AND ASSIGNMENT OF THE TNNT2 LOCUS TO CHROMOSOME 1Q

The troponin complex is located on the thin filament of striated muscl e and is composed of three component polypeptides: troponin T, troponi n I, and troponin C. Three troponin T genes have been described on the basis of molecular cloning in humans and other vertebrates. These are expressed in a tissue-specific manner and encode the troponin T isofo rms expressed in cardiac muscle, slow skeletal muscle, and fast skelet al muscle, respectively. Each of these genes is subject to alternative splicing, resulting in the production of multiple tissue-specific iso forms. We have cloned cDNAs encoding human cardiac troponin T from adu lt heart and have used these to demonstrate that multiple cardiac trop onin T mRNAs are present in the human fetal heart, resulting from alte rnative splicing in the 5' coding region of the gene. Hybridization of the cloned cDNAs to genomic DNA identifies a single-copy gene, and us ing somatic cell hybrid analysis, we have mapped the corresponding gen e locus (designated TNNT2) to the long arm of chromosome 1 (1cen-qter) . (C) 1994 Academic Press, Inc.