High impact information on Fzd4

• Norrin and Frizzled4 (Fz4) function as a ligand-receptor pair to control vascular development in the retina and inner ear [1].
• Although a recently identified, high-affinity FZD4 ligand Norrin (Norrie disease pseudoglioma homolog) is expressed in the ovary, adult Ndph-/- mice contain functional corpora lutea and do not phenocopy Fzd4-/- mice [2].
• Thus, Fzd4 appears to impact the formation of the corpus luteum by mechanisms that more closely phenocopy Prlr null mice [2].
• Histological and functional analyses of ovaries from timed mating pairs at Days 1.5-7.5 postcoitus (p.c.) indicate that the corpora lutea of the Fzd4-/- mice do not develop normally [2].
• Using deletion mapping, we localized the Frizzled4 (Fzd4) gene to the jdf/thymus and cardiac development intervals [3].

Biological context of Fzd4

• In contrast to the early cell proliferation and patterning effects classically ascribed to Wnts, the auditory and cerebellar phenotypes of fz4(-/-) mice implicate Frizzled signaling in maintaining the viability and integrity of the nervous system in later life [4].

Anatomical context of Fzd4

• In particular, fz4 is expressed in cerebellar Purkinje cells, esophageal skeletal muscle, and cochlear inner hair cells, and the absence of Fz4 in these cells is presumed to account for the fz4(-/-) phenotype [4].

References