Transcription Activator-like Effector Nuclease(TALEN)has been proven to be an effective tool for genome editing.It is composed of a TAL effector DNA binding domain and a non-specific DNA cleavage domain from the FokI endonuclease.The DNA binding domain recognizes specific DNA sequences by using the repeat variable diresidues(RVDs)in each repeat.But an engineered TAL effector(TALE)protein is capable of doing more things than just cleaving the DNA.Here we constructed a TALE activator and a TAL repressor by replacing the FokI cleavage domain with the VP16 constructive activation domain and the EVE constructive repression domain,respectively.And by means of whole mount in situ hybridization,we have found,in the system of zebrafish embryos,that these engineered TAL activator and TAL repressor are able to change the expression level of the zebrafish gene,in a efficient and specific manner.This kind of finding may contribute to a new strategy of gene knockup or knockdown,especially the later,which may provide an alternative to the commonly used gene knockdown tool in zebrafish,the morpholinos.