Expression of unc5 family genes in zebrafish brain during embryonic development

UNC5 family proteins are trans-membrane receptors which mediate both repulsion and attraction signals for the axonal growth cones. The UNC5 family proteins may also play critical roles in angiogenesis and carcinogenesis. Here we have determined the temporal and spatial expression patterns of unc5 gene family members (unc5a, unc5b, unc5c, unc5da and unc5db) by RT-PCR and in situ hybridization. RT-PCR results showed that all transcripts except unc5b were expressed maternally. While unc5b and unc5c transcript was detected at all time points between shield stage and 48 h post fertilization (hpf), unc5a, unc5da and unc5db showed expression at 24 hpf and later time points. In situ hybridization analysis revealed that unc5a, unc5da and unc5db transcripts were expressed in the telencephalon, parts of thalamus and hindbrain between 24 and 48 hpf. The expression patterns of unc5a-unc5da and unc5a-unc5db in the telencephalon showed substantial overlap by fluorescent in situ hybridization. Unc5b showed expression in the eye region, epiphysis and thalamus. Unc5c showed expression in the roof plate, the hindbrain and the mouth region. Our results provide a starting point to uncovering roles of unc5 gene family in zebrafish forebrain development and axonal outgrowth or guidance.