Expression patterns of the whole troponin C gene repertoire during Drosophila development.

The success of the genomic sequencing programs allows the discovery of additional family members of genes encoding known functions. This is the case of the Troponin C gene repertoire in Drosophila melanogaster. We have found two new Troponin C genes, DmTpnC41F and DmTpnC25D, increasing to five the total number of Troponin C genes identified in this species. The comparative characterization of the five Troponin C genes in D. melanogaster demonstrates considerable variation in gene structure and expression pattern. Expression of one gene, DmTpnC41F, has more restricted tissue specificity than the rest of the TpnC genes and, with the chromosomically linked DmTpnC41C, is expressed specifically in the adult thorax. The new gene, DmTpnC25D is expressed during development more broadly than the rest. In adults, it is highly expressed in the adult head. Finally, the other two genes, DmTpnC47D and DmTpnC73F, show a high embryonic/larval expression and in adults are expressed almost exclusively in the abdomens. The functional adaptive changes that may have evolved during the expansion of this gene family are briefly discussed in terms of the expression patterns, gene and protein structures leading to a simpler, more systematic nomenclature of the gene family.