Abstract: ATG5 as an abbreviation of autophagy related gene 5 is an importantgene for the formation of autophagosome,and plays a vital role in the maturation of autophagy regulation.In this study,a cDNA sequence of ATG5 was first cloned in Pacific cod Gadusmacrocephalus using gene cloning,and was found to be 895 bp encoding 275 amino acid residues with molecular weight of about32 200 in length with a whole open reading frame(ORF).The nucleotide sequence alignment showed that there was as high as similarity of87.27%in ATG5 among Pacific cod, Nile tilapia Oreochromis niloticus,and half-smooth tongue-sole Cynoglossus semilaev.The phylogenetic tree constructed by ATG5 nucleotide sequences of Pacific cod and some other animals reflected a genetic relationship which conformed to the viewpoint of traditional taxonomy.The amino acid sequence analysis revealed that ATG5 had high conservation.The expression of ATG5 in various tissues of Pacific cod using relative quantitative PCR and the absolute quantitative PCR showed that the higher expression levels of ATG5 mRNA were observed in liver,spleen and kidney than in other tissues,with 11.617 08 copies/ng in gill,20.449 25 copies/ng in kidney,19.706 87 copies/ ng in spleen,4.839 84 copies/ng in brain,27.434 97 copies/ng in liver,and 2.954 75 copies/ng inmuscle.The findings lay the foundation for further study of the phagocytosismechanism and provide basic data with understanding of immunemechanisms in Pacific cod.
2015, Vol. 30 
