Troponin T mRNA and protein isoforms in the human left ventricle: Pattern of expression in failing and control hearts

Laurence Mesnard-Rouiller, Jean Jacques Mercadier, Gillian Butler-Browne, Michele Heimburger, Damien Logeart, Paul D. Allen, Françoise Samson

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

We and others have previously cloned several cDNAs of human cardiac troponin T (cTnT), demonstrating the multiplicity of cTnT isoforms in the human heart. Four of them named cTnT1, 2, 3 and 4 result from a combinatorial alternative inclusion of 30- and 15-nucleotides in the 5' coding region of the cDNAs. In failing human ventricles, increased expression of cTnT4 has been reported at the protein level. More recent RT-PCR experiments showed increased expression of fetal-type splicing products in the 5' region, one of them corresponding to cTnT1. To clarify this issue, we examined the accumulation of the 4 cTnT mRNA and protein species in left ventricular specimens at the time of heart transplantation, and in control left ventricular samples using RNase protection and Western blotting. In all samples, cTnT3 was the major mRNA isoform, cTnT4 a minor isoform while cTnT1 and cTnT2 mRNAs were present but barely detectable. At the protein level, cTnT3, 4 and 1 were detected with the same relative abundance as that seen at the mRNA level. In addition, we detected a fourth TnT species of very low abundance corresponding either to a skeletal or to a 'short' cardiac TNT isoform. Compared to controls, increased levels of cTnT4 mRNA and protein were detected in only half the failing ventricles independently of the cause of failure, suggesting that this increase map not be a general characteristic of left ventricular failure but instead could be related to stress. Unexpectedly, we found a decrease in cTnT1 protein expression in all failing ventricular samples studied, compared to controls.

Original languageEnglish (US)
Pages (from-to)3043-3055
Number of pages13
JournalJournal of Molecular and Cellular Cardiology
Volume29
Issue number11
DOIs
StatePublished - Nov 1997
Externally publishedYes

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Keywords

  • Gene expression
  • Heart failure
  • Human heart
  • Stress
  • Troponin T

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

Cite this

Mesnard-Rouiller, L., Mercadier, J. J., Butler-Browne, G., Heimburger, M., Logeart, D., Allen, P. D., & Samson, F. (1997). Troponin T mRNA and protein isoforms in the human left ventricle: Pattern of expression in failing and control hearts. Journal of Molecular and Cellular Cardiology, 29(11), 3043-3055. https://doi.org/10.1006/jmcc.1997.0519