Premium
Suppression of atrial myosin gene expression occurs independently in the left and right ventricles of the developing mouse heart
Author(s) -
Zammit Peter S.,
Kelly Robert G.,
Franco Diego,
Brown Nigel,
Moorman Antoon F.M.,
Buckingham Margaret E.
Publication year - 2000
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/(sici)1097-0177(200001)217:1<75::aid-dvdy7>3.0.co;2-l
Subject(s) - ventricle , biology , myosin , heart development , embryonic heart , cardiac ventricle , anatomy , medicine , myh6 , myosin light chain kinase , microbiology and biotechnology , embryonic stem cell , myh7 , gene , genetics
Many cardiac genes are broadly expressed in the early heart and become restricted to the atria or ventricles as development proceeds. Additional transcriptional differences between left and right compartments of the embryonic heart have been described recently, in particular for a number of transgenes containing cardiac regulatory elements. We now demonstrate that three myosin genes which become transcriptionally restricted to the atria between embryonic day (E) 12.5 and birth, α‐myosin heavy chain (MHC), myosin light chain (MLC) 1A and MLC2A, are coordinately downregulated in the compact myocardium of the left ventricle before that of the right ventricle. α‐MHC protein also accumulates in the right, but not left, compact ventricular myocardium during this period, suggesting that this transient regionalisation contributes to fktal heart function. dHAND and eHAND, basic helix‐loop‐helix transcription factors known to be expressed in the right and left ventricles respectively at E10.5, remain regionalised between E12.5 and E14.5. Downregulation of α‐MHC, MLC1A, and MLC2A in iv/iv embryos, which have defective left/right patterning, initiates in the morphological left (systemic) ventricle regardless of its anatomical position on the right or left hand side of the heart. This points to the importance of left/right ventricular differences in sarcomeric gene expression patterns during fktal cardiogenesis and indicates that these differences originate in the embryo in response to anterior‐posterior patterning of the heart tube rather than as a result of cardiac looping. Dev Dyn 2000;217:75–85. © 2000 Wiley‐Liss, Inc.