Atrial and Ventricular Myosin Heavy-chain Expression in the Developing Chicken Heart: Strengths and Limitations of Non-radioactive In Situ Hybridization

Abstract

Myosin heavy-chain (MHC) isoforms are major structural components of the contractile apparatus of the heart muscle. Their spatio-temporal patterns of expression have been used as a tool to dissect cardiac development and differentiation. Although extensively investigated, controversy still exists concerning the expression patterns of atrial (AMHC), ventricular (VMHC), and cardiac myosin heavy-chain (CMHC) during development in the heart. In this study, we describe that probe length, probe concentration, and staining time in the non-radioactive in situ hybridization procedure seriously influence the observed pattern of MHC expression and the subsequent interpretation, explaining the divergent opinions in the field. Using a variety of external and internal controls for the in situ hybridization procedure, we demonstrate that both AMHC and VMHC are expressed throughout the entire heart tube during early development. During subsequent development, VMHC becomes restricted to the ventricles, whereas AMHC remains expressed in the atria, and, at substantially lower levels, is detected in the ventricles. These results are discussed in the context of methodological constraints of demonstrating patterns of gene expression. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.

Synergistic Effect of Feeding <i>Aspergillus Awamori </i>and <i>Saccharomyces Cerevisiae</i> on Growth Performance in Broiler Chickens; Promotion of Protein Metabolism and Modification of Fatty acid Profile in the Muscle

“…In fact, the mRNAs of actin and myosin were increased synergistically by the combination of A. awamori and S. cerevisiae, suggesting activation of pathways related to the skeletal muscle protein synthesis. These genes are related to the growth and development of muscle fibers (Somi et al, 2006;Guobin et al, 2011). These results support our hypothesis that decreased skeletal muscle protein breakdown is responsible for the stimulation of skeletal muscle growth caused by feeding A. awamori and S. cerevisiae.…”

Beneficial effects of Aspergillus awamori in broiler nutrition

“…However, mRNA expressions of beta-actin, myosin and pax-7, which are related to the growth and development of muscle fibre (Somi et al, 2006;Chang et al, 2011), were all increased but only slightly by feeding A. awamori as reported by Saleh et al(2012a). Therefore, these results suggest the idea that the promotion of muscle growth by feeding A. awamori is due to the suppression of skeletal muscle protein degradation rather than the enhancement of muscle protein synthesis.…”

Building the vertebrate heart - an evolutionary approach to cardiac development

“…On the contrary other proteins like α myosin heavy chain (MHCα) or myosin light chain 1A (MLC1A) are expressed at different levels in both atria and ventricles (Lyons et al, 1990). MLC2v also accumulates in the ventricle of avians (Somi et al, 2006). Nevertheless, how chamber identity is defined is an aspect of cardiac development that still needs much attention.…”