The Functional Study Of BMP2 Gene In The Heart Development Of Zebrafish

Heart development is a complex processes,which is strictly controlled by a number of signal pathways.transforming growth factor-?(TGF-?)plays a promoting role in the heart development in this process.BMP2(Bone Morphogenetic Protein 2)is a member of transforming growth factor-?(TGF-?)superfamily,it is a gene of the BMPs family that has been widely researched.Studies showed that the BMP2 gene plays an important role in the early development of embryo.In order to study the role of BMP2 gene in zebrafish heart development,we use the zebrafish as a model animal.Bioinformatics analysis results indicate that BMP2 protein between species evolution is conservative.We explore the spatial and temporal expression patterns of BMP2 in zebrafish.RT-PCR results showed that transcripts of BMP2 were expressed in zebrafish embryos at early developmental stages and in different organs.We here show that strong expression of BMP2 was found in 4h-12 h of embryonic development and in brain,heart,liver,gill,fin and reproductive organs.we successfully identified the expression pattern of BMP2 gene through whole-mount in situ hybridization to zebrafish embryos.Though synthetise a specific BMP2 Morpholino to inhibit BMP2 gene expression in the development of the zebrafish,while knockdown of BMP2 in embryos resulted in different degrees of malformation in the heart,including unable to loop normly,pericardialcysts,weak blood circulation,blood retention,heartbeat slow down and death.We found that the group of MO mortality and malformation rate of zebrafish was obviously higher than that of control group.We used the capped mRNA of BMP2 gene to conduct the rescue experiment and the result showed that Hand2 mRNA could well rescue the malformations in the zebrafish embryos with BMP2 protein expression knocked-down by the specific morpholino of this gene and has a lower mortality and malformation.In addition,QRT-PCR results showed that an different levels of regulation of cardiac marker genes SMAD4,NKX2.5,CMLC2,MEF2 C,TBX5,GATA4 and HAND2 was observed in the embryos when knocking down the expression of BMP2 by the morpholino,which suggested that BMP2 gene affects heart development through regulating heart development related transcription factors.But,we need more research to clarify BMP2 though which pathway to affect zebrafish heart development.