Lateral line, nervous system, and maternal expression of Frizzled 7a during zebrafish embryogenesis.

We have isolated and mapped a new wnt receptor frizzled family member, zebrafish frizzled 7a. Fz7a and a previously reported zebrafish fz7 (El-Messaoudi and Renucci, 2001) make an orthologous gene pair, however, they display distinct expression patterns. Fz7a shows strong maternal as well as zygotic expression. Fz7a transcript is enriched dorsally starting with the shield stage. At the end of gastrulation, Fz7a is abundantly expressed within anterior neuroectoderm and expressed more weakly within lateral mesoderm. Fz7a is detected during somitogenesis within the central nervous system, somatic and posterior lateral mesoderm. At 24hpf, fz7a is expressed in migrating lateral line primordium. At 48hpf, fz7a is detected in the ear, pectoral fin bud, and within neuromasts, which had originated from the lateral line primordium. Radiation hybrid mapping using panel LN54 (Hukriede et al., 1999) places fz7a on linkage group 6, linked to the marker fi11h08 (distance 0.00cR, LOD score 14.1). To prove that fz7 and fz7a are indeed different genes we mapped fz7 as well using the same LN54 panel. Fz7 mapped to linkage group 9 with a LOD of 12.5, 27.31 cR from wnt 10a in between markers IBD2759 and fb50e04.