The zebrafish sensory posterior lateral line(pLL)has become an attractive model for studying collective cell migration and cell morphogenesis.Recent studies have indicated that chemokine,Wnt/β-catenin,Fgf,and Delta-Notch signaling pathways participate in regulating pLL development.However,it remains unclear whether TGFβsignaling pathway is involved in pLL development.Here we report a critical role of TGFβ1 in regulating morphogenesis of the pLL primordium(pLLP).The tgfβ1a gene is abundantly expressed in the lateral line primordium.Knockdown or knockout of tgfβ1a leads to a reduction of neuromast number,an increase of inter-neuromast distance,and a reduced number of hair cells.The aberrant morphogenesis in embryos depleted of tgfβ1a correlates with the reduced expression of atoh1a,deltaA,and n-cadherin/cdh2,which are known important regulators of the pLLP morphogenesis.Like tgfβ1a depletion,knockdown of smad5 that expresses in the pLLP,affects pLLP development whereas overexpression of a constitutive active Smad5 isoform rescues the defects in embryos depleted of tgfβ1a,indicating that Smad5 mediates tgfβ1a function in pLLP development.Therefore,TGFβ/Smad5 signaling plays an important role in the zebrafish lateral line formation.
展开▼
