Expression pattern of mouse sFRP-1 and mWnt-8 gene during heart morphogenesis.
The Wnt genes encode a large family of secreted proteins that play a key role in embryonic development and tissue differentiation in many species (Rijsewijk et al., 1987; Nusse and Varmus, 1992). Genetic and biochemical studies have suggested that the frizzled proteins are cell surface receptors for Wnts (Vinson et al., 1989; Chan et al. , 1992; Bhanot et al., 1996; Wang et al., 1996). In parallel, a number of secreted frizzled-like proteins with a conserved N-terminal frizzled motif have been identified (Finch et al., 1997; Melkonyan et al., 1997; Rattner et al., 1997). One of these proteins, FrzA, the bovine counterpart of the murine sFRP-1 (93% identity) is involved in vascular cell growth control, binds Wg in vitro and antagonizes Xwnt-8 and hWnt-2 signaling in Xenopus embryos (Xu et al. , 1998; Duplàa et al., 1999). In this study, we report that sFRP-1 is expressed in the heart and in the visceral yolk sac during mouse development, and that sFRP-1 and mWnt-8 display overlapping expression patterns during heart morphogenesis. From 8.5 to 12.5 d.p. c., sFRP-1 is expressed in cardiomyocytes together with mWnt-8 but neither in the pericardium nor in the endocardium; at 17.5 d.p.c., they are no longer present in the heart. In mouse adult tissues, while sFRP-1 is highly detected in the aortic endothelium and media and in cardiomyocytes, mWnt-8 is not detected in these areas. Immunoprecipitation experiments demonstrates that FrzA binds to mWnt-8 in cell culture experiments.
Jaspard
B
B
INSERM U441, Avenue du Haut Lévêque, 33 600, Pessac, France.
Couffinhal
T
T
Dufourcq
P
P
Moreau
C
C
Duplàa
C
C
D000818:Animals; D015703:Antigens, CD / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D003598:Cytoskeletal Proteins; D005260:Female; D027261:Fusion Regulatory Protein-1; D015870:Gene Expression; D006321:Heart / Q000196:embryology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009024:Morphogenesis; D011506:Proteins / Q000235:genetics*; D051153:Wnt Proteins; D029961:Zebrafish Proteins
D015703:Antigens, CD; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D027261:Fusion Regulatory Protein-1; D011506:Proteins; D051153:Wnt Proteins; D029961:Zebrafish Proteins; C094521:wnt8a protein, zebrafish