The long-term goal of this project is to understand mechanisms of cardiac cell differentiation. The specific goals of this proposal are to identify genes important for cardiac valve formation in zebrafish and analyze their function. Cardiac valves are formed at several places along the vertebrate heart tube including the atrioventricular (AV) boundary which has been the focus of our studies. During the process of AV valve formation, myocardial cells at the AV boundary induce a subset of the underlying endocardial cells to undergo an epithelial to mesenchymal transition (EMT) and form an endocardial cushion. This cushion is later remodeled into a valve. Studies in chick and mouse embryos have led to the identification and analysis of several molecules important for distinct steps in valve formation but clearly additional molecules critical for this process remain to be identified. Previous genetic screens in zebrafish have led to the identification of two mutations that affect valve formation, jekyll and cardiofunk. We have recently isolated the Jekyll gene through a positional cloning approach and found that it encodes UDP-glucose dehydrogenase, an enzyme that primes sugars to be added into glycosaminoglycan (GAG) chains. GAG chains are the building blocks of Hyaluronic acid and are also covalently linked to proteoglycans. In order to understand the role of jekyll and cardiofunk in regulating valve formation, we propose the following specific aims: 1) further analyze their valve phenotype through histological analyses, gene and protein expression studies, and cell transplantation experiments; 2) utilize a transgenic line, generated in our lab, that expresses GFP in all endothelial, including endocardial, cells to examine valve formation in real time both in wild-type and in mutant embryos; and 3) map cardiofunk genetically and initiate its isolation by a positional cloning approach. We will also conduct large-scale genetic screens in diploid embryos to identify additional mutations affecting cardiac valve formation. We will begin to analyze the mutations defining new loci in order to dissect the role these genes play in cardiac valve formation. These molecular genetic studies of cardiac valve formation should lead to the identification of critical regulators of this process as well as to a detailed understanding of their function. This information should enhance our understanding and ability to diagnose, and possibly correct, valve and septation defects in humans.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL054737-07
Application #
6537212
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Program Officer
Pearson, Gail D
Project Start
1996-06-01
Project End
2006-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
7
Fiscal Year
2002
Total Cost
$285,500
Indirect Cost
Name
University of California San Francisco
Department
Biochemistry
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Zhang, Qiang; Huang, Hai; Zhang, Luqing et al. (2018) Visualizing Dynamics of Cell Signaling In Vivo with a Phase Separation-Based Kinase Reporter. Mol Cell 69:334-346.e4
Schepis, Antonino; Barker, Adrian; Srinivasan, Yoga et al. (2018) Protease signaling regulates apical cell extrusion, cell contacts, and proliferation in epithelia. J Cell Biol 217:1097-1112
Reade, Anna; Motta-Mena, Laura B; Gardner, Kevin H et al. (2017) TAEL: a zebrafish-optimized optogenetic gene expression system with fine spatial and temporal control. Development 144:345-355
Pestel, Jenny; Ramadass, Radhan; Gauvrit, Sebastien et al. (2016) Real-time 3D visualization of cellular rearrangements during cardiac valve formation. Development 143:2217-27
Ahuja, Suchit; Dogra, Deepika; Stainier, Didier Y R et al. (2016) Id4 functions downstream of Bmp signaling to restrict TCF function in endocardial cells during atrioventricular valve development. Dev Biol 412:71-82
Clay, Hilary; Wilsbacher, Lisa D; Wilson, Stephen J et al. (2016) Sphingosine 1-phosphate receptor-1 in cardiomyocytes is required for normal cardiac development. Dev Biol 418:157-165
Matsuoka, Ryota L; Marass, Michele; Avdesh, Avdesh et al. (2016) Radial glia regulate vascular patterning around the developing spinal cord. Elife 5:
To, Tsz-Leung; Schepis, Antonino; Ruiz-González, Rubén et al. (2016) Rational Design of a GFP-Based Fluorogenic Caspase Reporter for Imaging Apoptosis In Vivo. Cell Chem Biol 23:875-882
Reischauer, Sven; Stone, Oliver A; Villasenor, Alethia et al. (2016) Cloche is a bHLH-PAS transcription factor that drives haemato-vascular specification. Nature 535:294-8
Orr, Nathan; Arnaout, Rima; Gula, Lorne J et al. (2016) A mutation in the atrial-specific myosin light chain gene (MYL4) causes familial atrial fibrillation. Nat Commun 7:11303

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