This proposal seeks to establish correlations -- in response to a defined induction -- between chromatin changes, the appearance of cell-specific markers, and cell surface changes which result in three-dimensional heart morphogenesis. In the first of two unique methodological approaches, an affinity method is being developed to isolate active myocyte chromatin, which will be characterized in terms of two nuclear proteins which markedly change during skeletal myogenesis: ubiquitinated histone H2A and newly synthesized histone H3.3. The accumulation of H3.3 messenger RNA and protein levels during muscle development and maturation will help elucidate its role in maintenance of the striated muscle differentiated state. The second, related approach utilizes a novel heart development culture system which enables analysis of the effects of interacting embryonic tissues during morphogenesis. Using techniques of in situ hybridization histochemistry and immunocytochemistry, this model, which faithfully recapitulates in vivo cardiogenesis, will be used to test the hypothesis that the anterior foregut endoderm secretes proteins, to be characterized, which induce terminal differentiation and morphogenesis in precardiac mesoderm. It is proposed that this induction elicits the following sequence of events: (i) expression of histone H3.3 mRNA and its translation products, signaling chromatin structural rearrangements permissive for cardiogenesis, (ii) expression of mRNA's for cardiac-specific contractile proteins, and (iii) expression of cell:cell (CAM's) and cell: substrate (SAM's) adhesion molecules which mediate cellular movements in morphogenesis, culminating in the development of a three-dimensional, contractile organ. These studies will help elucidate mechanisms which regulate the induction and maintenance of the cardiac differentiated state, providing insights into the etiology of disorders including congenital anomalies and cardiomyopathies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL039829-04
Application #
3356753
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Project Start
1988-03-01
Project End
1993-02-28
Budget Start
1991-03-01
Budget End
1992-02-29
Support Year
4
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Medical College of Wisconsin
Department
Type
Schools of Medicine
DUNS #
073134603
City
Milwaukee
State
WI
Country
United States
Zip Code
53226
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Rudy-Reil, Diane; Lough, John (2004) Avian precardiac endoderm/mesoderm induces cardiac myocyte differentiation in murine embryonic stem cells. Circ Res 94:e107-16
Zhu, Xiaolei; McAllister, Donna; Lough, John (2003) Inhibition of the cardiac alpha-actin gene in embryonic cardiac myocytes by dominant-negative serum response factor. Anat Rec A Discov Mol Cell Evol Biol 271:315-21
McAllister, Donna; Merlo, Xanthi; Lough, John (2002) Characterization and expression of the mouse tat interactive protein 60 kD (TIP60) gene. Gene 289:169-76
Lough, John W (2002) Transient expression of TIP60 protein during early chick heart development. Dev Dyn 223:419-25
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Gont, L; Lough, J (2000) Differential expression of cSmad1 and cSmad5 in the primitive streak during chick embryo gastrulation. Anat Rec 260:102-5
Zhu, X; Sasse, J; Lough, J (1999) Evidence that FGF receptor signaling is necessary for endoderm-regulated development of precardiac mesoderm. Mech Ageing Dev 108:77-85
Barron, M; McAllister, D; Smith, S M et al. (1998) Expression of retinol binding protein and transthyretin during early embryogenesis. Dev Dyn 212:413-22

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