To investigate the effects of docosahexaenoic acid(DHA)on the expression profiles of B cell CLL/lymphoma-2(Bcl-2)in grass carp(Ctenopharyngodon idella)different tissues and adipocyte in vitro,the rapid amplification of cDNA ends(RACE)technique was used to clone the full-length cDNA of Bcl-2 gene of grass carp,and the real-time PCR(qRT-PCR)was employed in the analysis of gene expression pattern in different tissues and in the in-vitro cultured adipocyte of grass carp.The results revealed that the full-length Bcl-2 cDNA is 1 292 bp and contains a 5′-untranslated region with 133 bp and 3′-untranslated region with 784 bp.The open reading frame(ORF)has 375 nucleotides encoding 124 amino acids.The deduced amino acid sequences of Bcl-2 of grass carp displayed higher similarities with Cyprinus carpio(89.5%)and Danio rerio(91.1%),but lower identity to the other animals with the similarity ranging from 57.7% to 62.0%.The molecular weight of encoded protein was predicted at 14.14 ku with pIat 4.68.TheBcl-2 gene is widely expressed in heart,hepatopancreas,spleen,gills,kidney,muscle,intrapaneal fat body(IPF),brain,intestine and spermary.The highest expression level was observed in IPF,kidney,spermary and the lowest expression level was observed in muscle.The expression of other tissues was between IPF and muscle.After DHA treatment,the Bcl-2 expression was downregulated in the proliferation phase,but upregulated in the differentiation phase.This suggested the Bcl-2 was expressed widely,and DHA could regulate the expression of Bcl-2 gene.