| First Author | Ausoni S | Year | 1994 |
| Journal | J Biol Chem | Volume | 269 |
| Issue | 1 | Pages | 339-46 |
| PubMed ID | 8276817 | Mgi Jnum | J:16384 |
| Mgi Id | MGI:64465 | Doi | 10.1016/s0021-9258(17)42354-4 |
| Citation | Ausoni S, et al. (1994) Structure and regulation of the mouse cardiac troponin I gene. J Biol Chem 269(1):339-46 |
| abstractText | The gene coding for mouse cardiac troponin I (TnI) has been cloned and sequenced. The cardiac TnI gene contains 8 exons and has an exon-intron organization similar to the quail fast skeletal TnI gene except for the region of exons 1-3, which is highly divergent. Comparative analysis suggests that cardiac TnI exon 1 corresponds to fast TnI exons 1 and 2 and that cardiac exon 3, which codes for most of the cardiac-specific amino-terminal extension and has no counterpart in the fast gene, evolved by exon insertion/deletion. The amino acid sequence of cardiac TnI exon 4 shows limited homology (36% identity) with fast TnI exon 4 but is remarkably similar (79% identity) to the corresponding sequence of slow TnI, possibly reflecting an isoform-specific TnC-binding site. The cardiac TnI gene is one of the very few contractile protein genes expressed exclusively in cardiac muscle. To identify the regulatory sequences responsible for the cardiac-specific expression of this gene we transfected cultured cardiac and skeletal muscle cells with fragments up to 4.0 kilobases of the 5'-flanking region linked to a reporter gene. Deletion analysis reveals four major regions in the 5'-flanking sequence, a minimal promoter region, which directs expression at low level in cardiac and skeletal muscle cells, and two upstream cardiac-specific positive regions separated by a negative region. |
