Function Study Of Notch Family Genes In The Planarian,Dugesia Japonica

The Notch pathway is a cell-cell signaling pathway that is highly conserved across metazoa.Notch is frequently deployed to help establish cellular diversity in developing tissues.It achieves this through various means including binary cell fate decisions via lateral inhibition or induction,regulation of stem cell selfrenewal versus differentiation,modulation of cell proliferation or survival,and general roles in cellular differentiation.Freshwater planarian,Dugesia japonica,has robust regeneration capacity with plenty of neoblasts,and has become the model systems of regeneration.Therefore,studies of planarian biology will help the understanding of processes relevant to human development and health not easily studied in current invertebrate genetic systems.Therefore,studies of planarian regeneration mechanism and Notch functions will help the understanding of processes relevant to human development and health not easily studied in current invertebrate genetic systems at the molecular biological level.In this study,using bioinformatics,in situ hybridization,Real-time PCR,and RNA interference to study the function of Dj Notch family in planarians.Meanwhile,planarians was treated with DAPT to decrease Notch signal.The proliferation,differentiation and apoptosis of cells was observed,during the DAPT treatment,to investigate the function of Dj Notch in development and tissue homeostasis in planarians,Dugesia japonica.Here was the results:(1)There are six members in DjNotch,The deduced amino acid sequence of DjNotch1 and DjNotch2 has EGF-like repeats,LNR repeats,Transmembrane domain and Ankyrin repeats.The deduced amino acid sequence of Dj Notch3 only has EGF-like repeats,Dj Notch4 only has Transmembrane domain.The deduced amino acid sequence of Dj Notch5 and Dj Notch6 has EGF-like repeats and Transmembrane domain.(2)DjNotch family was broadly expression in mesenchymal tissue,and expressed specifically in the inner edge of the body.In the regeneration group,the specific signals presents starlike in mesenchymal tissue,which is centralized distribution in the blastema and the edge and middle line of planarian.(3)After the Dj Notch RNAi,planarians had regenerated asymmetric tail,pigment deposition black plaque,ectopic eyes.It is speculated that Dj Notch promotes cell apoptosis,influences eye development and body axis establishment.(4)During ten days of 100 nM DAPT treatment,intact planarians developed ectopic eyes,while regeneration planarians not only developed ectopic eyes,but also regenerated asymmetric tail and morphological abnormality.Simultaneously the level of cell proliferation and apoptosis was raise,which was seriously affecting physical coordination and tissue homeostasis.The above results indicate that Dj Notch family was broadly expression in mesenchymal tissue,and expressed specifically in the blastema and inner edge of the body,which affects in tissue regeneration and homeostasis in planarians.It was also found that Dj Notch family may be related to cell proliferation,migration,differentiation,apoptosis and body axis establishment.