Role of the Fetal and alpha/beta Exons in the Function of Fast Skeletal Troponin T Isoforms: Correlation with Altered Ca(2+) Regulation Associated with Development. Export

@article{citeulike:305655, abstract = {In mammalian fast skeletal muscle, constitutive and alternative splicing from a single troponin T (TnT) gene produce multiple developmentally regulated and tissue specific TnT isoforms. Two exons, alpha (exon 16) and beta (exon 17), located near the 3' end of the gene and coding for two different 14 amino acid residue peptides are spliced in a mutually exclusive manner giving rise to the adult TnTalpha and the fetal TnTbeta isoforms. In addition, an acidic peptide coded by a fetal (f) exon located between exons 8 and 9 near the 5' end of the gene, is specifically present in TnTbeta and absent in the adult isoforms. To define the functional role of the f and alpha/beta exons, we constructed combinations of TnT cDNAs from a single human fetal fast skeletal TnTbeta cDNA clone in order to circumvent the problem of N-terminal sequence heterogeneity present in wild-type TnT isoforms, irrespective of the stage of development. Nucleotide sequences of these constructs, viz. TnTalpha, TnTalpha+f, TnTbeta-f and TnTbeta are identical, except for the presence or absence of the alpha or beta and f exons. Our results, using the recombinant TnT isoforms in different functional in vitro assays, show that the presence of the f peptide in the N-terminal T1 region of TnT, has a strong inhibitory effect on binary interactions between TnT and other thin filament proteins, TnI, TnC and Tm. The presence of the f peptide led to reduced Ca(2+)-dependent ATPase activity in a reconstituted thin filament, whereas the contribution of the alpha and beta peptides in the biological activity of TnT was primarily modulatory. These results indicate that the f peptide confers an inhibitory effect on the biological function of fast skeletal TnT and this can be correlated with changes in the Ca(2+) regulation associated with development in fast skeletal muscle.}, address = {Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, 136 Harrison Avenue, Boston, MA 02111, USA.}, author = {Chaudhuri, Tathagata and Mukherjea, Monalisa and Sachdev, Sanjay and Randall, Jeffrey D D. and Sarkar, Satyapriya}, citeulike-article-id = {305655}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.jmb.2005.06.066}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/16081096}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=16081096}, day = {1}, doi = {10.1016/j.jmb.2005.06.066}, issn = {0022-2836}, journal = {J Mol Biol}, keywords = {alt, muscle, splicing}, month = {August}, posted-at = {2005-08-27 13:48:30}, priority = {2}, title = {Role of the Fetal and alpha/beta Exons in the Function of Fast Skeletal Troponin T Isoforms: Correlation with Altered Ca(2+) Regulation Associated with Development.}, url = {http://dx.doi.org/10.1016/j.jmb.2005.06.066}, year = {2005} }

TY - JOUR ID - citeulike:305655 L3 - citeulike-article-id:305655 N2 - In mammalian fast skeletal muscle, constitutive and alternative splicing from a single troponin T (TnT) gene produce multiple developmentally regulated and tissue specific TnT isoforms. Two exons, alpha (exon 16) and beta (exon 17), located near the 3' end of the gene and coding for two different 14 amino acid residue peptides are spliced in a mutually exclusive manner giving rise to the adult TnTalpha and the fetal TnTbeta isoforms. In addition, an acidic peptide coded by a fetal (f) exon located between exons 8 and 9 near the 5' end of the gene, is specifically present in TnTbeta and absent in the adult isoforms. To define the functional role of the f and alpha/beta exons, we constructed combinations of TnT cDNAs from a single human fetal fast skeletal TnTbeta cDNA clone in order to circumvent the problem of N-terminal sequence heterogeneity present in wild-type TnT isoforms, irrespective of the stage of development. Nucleotide sequences of these constructs, viz. TnTalpha, TnTalpha+f, TnTbeta-f and TnTbeta are identical, except for the presence or absence of the alpha or beta and f exons. Our results, using the recombinant TnT isoforms in different functional in vitro assays, show that the presence of the f peptide in the N-terminal T1 region of TnT, has a strong inhibitory effect on binary interactions between TnT and other thin filament proteins, TnI, TnC and Tm. The presence of the f peptide led to reduced Ca(2+)-dependent ATPase activity in a reconstituted thin filament, whereas the contribution of the alpha and beta peptides in the biological activity of TnT was primarily modulatory. These results indicate that the f peptide confers an inhibitory effect on the biological function of fast skeletal TnT and this can be correlated with changes in the Ca(2+) regulation associated with development in fast skeletal muscle. JF - J Mol Biol SN - 0022-2836 AD - Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, 136 Harrison Avenue, Boston, MA 02111, USA. TI - Role of the Fetal and alpha/beta Exons in the Function of Fast Skeletal Troponin T Isoforms: Correlation with Altered Ca(2+) Regulation Associated with Development. KW - alt KW - muscle KW - splicing AU - Chaudhuri, Tathagata AU - Mukherjea, Monalisa AU - Sachdev, Sanjay AU - Randall, Jeffrey D AU - Sarkar, Satyapriya PY - 2005/08/01/ UR - http://dx.doi.org/10.1016/j.jmb.2005.06.066 ER -