Genetic And Molecular Dissection Of Laterality In The Developing Heart
Funder
National Health and Medical Research Council
Funding Amount
$379,370.00
Summary
Vertebrate animals display an external bilateral symmetry. However, most internal organs are located asymmetrically and show profound left-right structural asymmetries during development. For each species, these laterality characteristics are constant. Inherited laterality disorders occur in humans and, although rare, are associated with high mortality rates due to discordant cardiovascular development. Moreover, subtle anomalies of laterality may underlie a host of congenital heart abnormalitie ....Vertebrate animals display an external bilateral symmetry. However, most internal organs are located asymmetrically and show profound left-right structural asymmetries during development. For each species, these laterality characteristics are constant. Inherited laterality disorders occur in humans and, although rare, are associated with high mortality rates due to discordant cardiovascular development. Moreover, subtle anomalies of laterality may underlie a host of congenital heart abnormalities. In early embryogenesis, the newly-formed heart tube loops to the right, an event which establishes the correct alignment of the future cardiac chambers. The direction of heart looping is determined by genetic pathways that establish laterality in the early embryo. A component of this pathway is a TGFbeta-family signalling molecule, nodal, which is activated on the left side of the forming heart and other organs. Nodal then activates the transcription factor gene Pitx2. The aim of this project is to examine the consequences of genetic inactivation of the mouse nodal and Pitx2 genes in the heart, and to discover cardiac genes downstream of these genes. We will specifically test the hypothesis that laterality contributes to heart chamber formation in addition to setting the direction of looping. Ablation of these genes in the whole embryo leads to complex defects that preclude analysis of their functions in the heart. To achieve heart-specific deletion, we will use a conditional gene ablation technology that exploits the bacteriophage recombinase, Cre. Genes downstream of Pitx2 and Nodal will be discovered using microarray technology, which allows us to screen exhaustively for changes in gene expression between different tissues. This project will help us solve the complex genetic basis of congenital cardiac abnormalities in humans, and will contribute to our understanding of how heart chambers form, potentially useful in stem cell-based therapies for the failing heart.Read moreRead less
Head Development: Genetic Determinants And Tissue Potency
Funder
National Health and Medical Research Council
Funding Amount
$947,116.00
Summary
Congenital malformations involving major defects of brain (anencephalus and related anomalies) and facial structures (ear, face and neck) are encountered in 3.4 and 1.4 per 10000 births respectively (Congenital Malformations Australia 1981-1996, National Perinatal Statistics Unit) and they constitute a substantial clinical burden. It is believed that these major structural defects usually result from abnormal development in the first trimester, which coincides with the time frame for the formati ....Congenital malformations involving major defects of brain (anencephalus and related anomalies) and facial structures (ear, face and neck) are encountered in 3.4 and 1.4 per 10000 births respectively (Congenital Malformations Australia 1981-1996, National Perinatal Statistics Unit) and they constitute a substantial clinical burden. It is believed that these major structural defects usually result from abnormal development in the first trimester, which coincides with the time frame for the formation of the basic components of the embryonic head in the mouse. Knowledge of the formation of the head in the mouse model is therefore relevant to the understanding of related developmental processes in early human development. This project which involves the application of sophisticated embryological and molecular analyses on mouse embryos generated by transgenesis and genetic manipulation provides a detailed studies of craniofacial morphogenesis in a mammalian model for early human development. The micro-manipulation procedures, embryo culture, fluorescence microscopy and the in situ hybridization are routinely performed in our laboratory, and most of the mouse lines are well established in my laboratory. Experiments proposed for this project that focus on the embryological and molecular analysis of normal and mutant embryos should discover new information on the cellular and molecular mechanisms that regulate head development. The knowledge will also offer insight into the pathogenesis of similar craniofacial malformations in other mutant embryos.Read moreRead less
A Fluorescent Zebrafish Model Of Endodermal Cell Migration.
Funder
National Health and Medical Research Council
Funding Amount
$535,333.00
Summary
The most catastrophic event in cancer progression is when individual cancer cells move to other areas of the body and develop into secondary tumours. This very complex process shows striking similarities to cell movements during embryogenesis. In this project, we use a model system, the zebrafish, to analyse how cells move during embryogenesis. We will determine the genes required for cell movements in the zebrafish embryo, so we can find the corresponding genes in human cancers.