cDNA cloning, characterization and expression of lipopolysaccharide and β-1,3-glucan binding protein (LGBP) gene from the Indian white shrimp Fenneropenaeus indicus.

A 1372bp full length cDNA of an LGBP gene was identified from the Indian white shrimp, Fenneropenaeus indicus. The open reading frame (ORF) of the F. indicus LGBP (Fein-LGBP) was 1164bp long, encoding a polypeptide of 388 amino acids. The Fein-LGBP deduced amino acid has conserved potential recognition motif for β-1, 3 linkages of polysaccharides and putative RGD (Arg-Gly-Asp) cell adhesion sites. Phylogenetic analysis revealed that the Fein-LGBP was grouped together with LGBPs of other crustaceans such as F. chinensis (91%, AAZ41363), Penaeus monodon (88%, AAM21213) and Litopenaeus vannamei (88%, ABU92557). Quantitative RT-PCR results showed that Fein-LGBP gene expression was up-regulated in hemocytes following a 6h challenge in response to peptidoglycan (PG) and Vibrio parahaemolyticus. Messenger RNA transcripts of Fein-LGBP were measured in hemocytes of F. indicus from different molting stages. The highest Fein-LGBP mRNA expression was observed in pre-molting stages (D0/1) when compared to post-molt stages (A and B) and inter-molt stages (C). Fein-LGBP is involved in the regulation and activation of the prophenoloxidase cascade.