Molecular cloning and transcriptional analysis of a newly identified anti-lipopolysaccharide factor gene in kuruma shrimp, Marsupenaeus japonicus

Aim: In the present study, we have cloned a new family of anti-lipopolysaccharide factor (ALF) from haemocytes of kuruma shrimp Marsupenaeus japonicus (MjALF2) using RACE method. Methods and Results: Transcriptional analysis of MjALF2 gene in the organs of healthy shrimp revealed prominent expression in gills and muscle. In vitro LPS stimulation in the lymphoid organ cells resulted in significant increase in expression at 48, 8 and 12 h poststimulation, compared to the nonstimulated cells. In vivo injection of V. penaeicida does not show any high expression in time course assay. Phylogenetic analysis showed MjALF2 is placed in the group closer to P. monodon isoform 1 and 2 than to MjALF1. The full-length MjALF2 gene consists of 558 bp with a 363 -bp open reading frame, encoding 121 amino acids. The deduced peptide contains a putative signal peptide of 22 amino acids with molecular mass of about 13 center dot 8 kDa molecular mass. The deduced amino acid sequence of MjALF2 showed 83 center dot 3 and 56 center dot 7% identity with ALF sequences of P. monodon. Conclusions: The present work revealed the presence of MjALF2 gene, which is highly expressed in gills and muscle of healthy kuruma shrimp. Further studies are required to clarify the involvement of MjALF2 in immune responses for using as a therapeutic agent. Significance and Impact of the Study: Antimicrobial peptides are promising potential therapeutic agents for disease control in aquaculture. Understanding the relation of MjALF2 with innate immunity mechanism will lead to develop better health management strategies for long-term sustainability of the shrimp industry.