The designation 'Wnt' was derived from two drosophila phenotypes 'wingless' and 'int'. The Wnt gene was first defined as a protooncogene, int1. Humans have at least 4 Wnt genes: Wnt7a gene is at 3p25 encoding a 349aa secreted glycoprotein. A patterning switch with different roles in different tissues. Wnt7a is secreted protein and binds to extracellular matrix. The mechanism of Wnt distribution (free diffusion, restricted diffusion and active transport) and all its possible cell receptors are still being determined. There is at least one WNT receptor called Frizzled (FZD). The Frizzled gene family encodes a seven-transmembrane receptor.
Muscle Development - Wnt signaling promotes AChR aggregation at the neuromuscular synapse in collaboration with agrin. Henriquez JP, Webb A, Bence M, Bildsoe H, Sahores M, Hughes SM, Salinas PC. Proc Natl Acad Sci U S A. 2008 Nov 19.
"Wnt proteins regulate the formation of central synapses by stimulating synaptic assembly, but their role at the vertebrate neuromuscular junction (NMJ) is unclear. Wnt3 is expressed by lateral motoneurons of the spinal cord during the period of motoneuron-muscle innervation. ...Wnt3 does not signal through the canonical Wnt pathway to induce cluster formation. Instead, Wnt3 induces the rapid formation of unstable AChR micro-clusters through activation of Rac1, which aggregate into large clusters only in the presence of agrin."
(More? Muscle Development)
Vascular Development - Canonical Wnt signaling regulates organ-specific assembly and differentiation of CNS vasculature. Stenman JM, Rajagopal J, Carroll TJ, Ishibashi M, McMahon J, McMahon AP. Science. 2008 Nov 21;322(5905):1247-50.
"The central nervous system (CNS) vasculature consists of a tightly sealed endothelium that forms the blood-brain barrier, whereas blood vessels of other organs are more porous. Wnt7a and Wnt7b encode two Wnt ligands produced by the neuroepithelium of the developing CNS coincident with vascular invasion. Using genetic mouse models, we found that these ligands directly target the vascular endothelium and that the CNS uses the canonical Wnt signaling pathway to promote formation and CNS-specific differentiation of the organ's vasculature"
(More? Vascular Development)
At least 3 separate signaling pathways have been identified in relation to Wnt singnaling.
Non-Canonical (Planar Cell Polarity Pathway)
Wnt-Calcium Ion Pathway
(data from Expasy)
"The OMIM database was initiated in the early 1960s by Dr. Victor A. McKusick as a catalog of mendelian traits and disorders, entitled Mendelian Inheritance in Man (MIM). Twelve book editions of MIM were published between 1966 and 1998. The online version, OMIM, was created in 1985 by a collaboration between the National Library of Medicine and the William H. Welch Medical Library at Johns Hopkins."
Molecular Biology of the Cell (4th Edn) Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter. New York: Garland Publishing; 2002.
Search Aug2005 "Wnt" ?? reference articles of which ?? were reviews.
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The Wnt gene Homepage by Roel Nusse