Distinct but redundant expression of the Frizzled Wnt receptor genes at signaling centers of the developing mouse brain

• Published in: Neuroscience Vol. 147; no. 3; pp. 693 - 711
• Main Authors: Fischer, T, Guimera, J, Wurst, W, Prakash, N
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 13.07.2007; Elsevier
• Subjects: Age Factors; Animals; Biological and medical sciences; Body Patterning - physiology; Brain - embryology; Brain - metabolism; cortical hem; Embryo, Mammalian; Embryonic Development - physiology; Frizzled Receptors - classification; Frizzled Receptors - genetics; Frizzled Receptors - metabolism; Fundamental and applied biological sciences. Psychology; Fzd; Gene Expression Regulation, Developmental - physiology; In Situ Hybridization; isthmic organizer; Mice; mid-/hindbrain boundary; Neurology; Phylogeny; Signal Transduction - physiology; Vertebrates: nervous system and sense organs; Wnt Proteins - metabolism; dorsal–ventral; A/P; MHB; Lrp; phosphate-buffered saline; fibroblast growth factor; low-density-lipoprotein-related protein; embryonic day; human Frizzled; mouse Frizzled (receptor); mid-/hindbrain boundary; cortical hem; PBS; Ror2/Ryk; subventricular zone; LOF; ventricular zone; Fgf; polymerase-chain-reaction; MZ; zona limitans intrathalamica; Frizzled (receptor); base pairs; CRD; hFZD; PCR; anterior–posterior; in situ hybridization; orphan tyrosine kinase-related receptors; loss-of-function; IsO; VZ; E; marginal zone; D/V; accession; bp; mFzd; SVZ; ZLI; Wnt; ISH; isthmic organizer; Acc; wingless/int (protein); cysteine-rich domain; Fzd; rhombomere 1; r1; Rodentia; Central nervous system; Encephalon; Signal transduction; Vertebrata; Mammalia; Mouse; Animal; Development; Biological receptor
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2007.04.060

Abstract The establishment of the regional subdivisions of the vertebrate CNS is accomplished through the activity of different neuroepithelial organizing centers. The wingless/int (Wnt) family of secreted glycoproteins, among other factors, plays a crucial role in signaling from these centers. Wnt1 secreted from the boundary between the mid- and hindbrain, for instance, controls the development of this brain region and of associated neuronal populations. Different Wnts secreted from the caudomedial pallium, the cortical hem, pattern the adjacent hippocampal field. The first step in Wnt signal transduction is binding of the Wnt ligand to its receptors, the seven-pass transmembrane Frizzled proteins. Inactivation of different Frizzled genes in mice have revealed an extensive functional redundancy between these receptors. In order to discriminate between a possible participation of different Frizzled receptors in the transduction of Wnt signals at the mid-/hindbrain boundary and the cortical hem, we have performed a detailed expression study of the 10 known murine Frizzled genes at crucial stages of mouse embryonic development. Our analysis reveals a highly dynamic yet distinct expression pattern of individual Frizzled genes in the anterior neural tube of the developing mouse embryo. The overlapping spatio-temporal expression of at least two and up to six Frizzled genes in any region of the developing mouse brain, however, also suggests a vast functional redundancy of the murine Frizzled receptors. This redundancy has to be taken into consideration for future analyses of Frizzled receptor function at these signaling centers in the mouse.