451. Remodeling of the hypertrophied human myocardium by cardiac bHLH transcription factors.
- Author
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Ritter O, Haase H, Schulte HD, Lange PE, and Morano I
- Subjects
- Base Sequence, Basic Helix-Loop-Helix Transcription Factors, Cardiomyopathy, Hypertrophic genetics, Cardiomyopathy, Hypertrophic pathology, DNA Primers genetics, DNA-Binding Proteins genetics, Gene Expression, Heart Ventricles metabolism, Helix-Loop-Helix Motifs genetics, Helix-Loop-Helix Motifs physiology, Humans, Myocardium pathology, Myosin Light Chains genetics, Myosin Light Chains metabolism, RNA, Antisense genetics, RNA, Antisense metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, Tetralogy of Fallot genetics, Tetralogy of Fallot metabolism, Tetralogy of Fallot pathology, Transcription Factors genetics, Zebrafish Proteins, Cardiomyopathy, Hypertrophic metabolism, DNA-Binding Proteins metabolism, Myocardium metabolism, Transcription Factors metabolism
- Abstract
The basic helix-loop-helix transcription factors eHAND and dHAND are involved in developmental cardiac growth and differentiation. We investigated HAND gene expression in the normal and in the hypertrophied right and left ventricle of patients with tetralogy of Fallot (ToF) and hypertrophic obstructive cardiomyopathy (HOCM). HAND mRNA was constitutively expressed in the hypertrophied heart and increased in the hypertrophic tissue of both patient groups. HAND genes had a complementary left-right cardiac asymmetry of expression with dHAND predominantly in the right and eHAND in the left ventricle. The two cardiac bHLH factors have the ability to form heterodimers with the ubiquitous bHLH protein E12, subsequently recognizing E-boxes in the promoter region of target genes like ALC-1. We found a highly significant positive correlation between HAND and ALC-1 mRNA. The total ALC-1 protein level in ToF was smaller than in HOCM, although ALC-1 mRNA as well as HAND mRNA levels were significantly higher. ToF patients expressed around four times more ALC-1 mRNA for similar amounts of ALC-1 than HOCM patients. Suggesting disturbed ALC-1 translation in ToF, we found ALC-1 antisense mRNA expression in the hypertrophied, but not in the normal, ventricles. The higher the antisense/sense ALC-1 mRNA ratio, the lower ALC-1 protein was expressed., (Copyright 1999 Wiley-Liss, Inc.)
- Published
- 1999
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