Characterization, expression and functional analysis of Hsp40 during LPS challenge in blood parrot Amphilophus citrinellus ×Vieja melanura.

ABSTRACT

Heat shock protein 40 belonging to heat shock protein family plays an important role in the immune responses of organisms. In this study, the full length cDNA of Hsp40 was 2426 bp including a 1368 bp open reading frame (ORF) encoding 455 amino acids with a molecular weight of 49.16 kDa and a theoretical isoelectric point of 9.34 in blood parrot Vieja synspila ♀ × Amphilophus citrinellus ♂, an important ornamental fish in China. It had three conserved domains DnaJ, CRR and DnaJ_C. Phylogenetic analysis showed that the sequence of Hsp40 among species was conserved, and the blood parrot Hsp40 was closely related to Neolamprologus brichardi. Blood parrot Hsp40 mRNA could be detected in all of the tissues examined and mainly distributed in the cytoplasm. The expression of Hsp40 was upregulated during lipopolysaccharide (LPS) challenge. Upregulated Hsp40 inhibited the activity of nuclear factor κB (NF-κB) and activated protein 1 (AP-1) and reduced the ratio of Bax/Bcl-2 mRNA expression. This study provides a theoretical basis for further exploring the role of Hsp40 gene in the anti-bacterial immunity of blood parrot.