Elsevier

Developmental Biology

Volume 231, Issue 1, 1 March 2001, Pages 252-264
Developmental Biology

Regular Article
Pitx2 Expression Defines a Left Cardiac Lineage of Cells: Evidence for Atrial and Ventricular Molecular Isomerism in the iv/iv Mice

https://doi.org/10.1006/dbio.2000.0133Get rights and content
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Abstract

The homeobox gene Pitx2 has been characterized as a mediator of left-right signaling in heart, gut, and lung morphogenesis. However, the relationship between the developmental role of Pitx2 and its expression pattern at the organ level has not been explored. In this study we focus on the role of Pitx2 in heart morphogenesis. Chicken Pitx2 transcripts are present in the left portion of the cardiac crescent and in the left side of the heart tube. Through looping Pitx2 is present in the left atrium, in the ventral portion of the ventricles and in the left-ventral part of the outflow tract. Mouse Pitx2 shows a similar developmental profile of expression. To test whether Pitx2 represents a lineage marker we have tagged the left portion of the chicken cardiac tube with fluorescent DiD. Labeled cells were found at HH16 in the left atrium and in the ventral region of the ventricles and the outflow tract. In the iv/iv mouse model of cardiac heterotaxia Pitx2 was abnormally expressed in the atrial and in the ventricular chambers. Furthermore, altered Pitx2 expression correlated with the occurrence of DORV. Our data reveal the existence of molecular isomerism not only in the atrial, but also in the ventricular compartment of the heart.

Keywords

left-right asymmetry
heart development
cell lineage
Pitx2
isomerism

Cited by (0)

1

To whom correspondence should be addressed at present address: Department of Biomedical Sciences, University of Padua, Via G. Colombo, 3, 35121-Padova, Italy. Fax: 0039-049-8276040. E-mail:[email protected].

2

Present address: Department of Experimental Biology, Faculty of Health and Experimental Sciences, Universty of Jaen, 23071 Jaen, Spain.