Assignment of the human fast skeletal troponin T gene (TNNT3) to chromosome 11p15.5: Evidence for the presence of 11pter in a monochromosome 9 somatic cell hybrid in NIGMS mapping panel 2

Human fast skeletal troponin T (TnT(f)), the tropomyosin binding component of the multisubunit troponin complex, plays an important role in the Ca²⁺ regulation of striated muscle contraction. Specific primers designed from the 3' end of human TnT(f) cDNA were used to amplify an intronic region by polymerase chain reaction (PCR). This TnT(f)-specific PCR product was detected from two somatic cell hybrids containing human chromosomes 9 and 11, respectively, in NIGMS mapping panel 2. However, further studies with other somatic hybrid cell lines (Bios Laboratory) localized the TnT(f) gene (HGMW- approved symbol TNNT3) only to chromosome 11. This observation was further confirmed by fluorescence in situ hybridization with a 12-kb TnT(f) genomic probe generated by extended PCR, showing the sublocalization of the gene to band p15.5 on chromosome 11. This locus is of specific interest, as Beckwith- Wiedemann syndrome and various childhood and adult tumor-related abnormalities have been mapped to this region. The study also indicates the presence of an 11pter region in the NIGMS cell hybrid GM10611, which has previously been reported to contain only human chromosome 9.