Molecular cloning of peroxinectin gene and its expression in response to peptidoglycan and Vibrio harveyi in Indian white shrimp Fenneropenaeus indicus.

The cDNA sequence of peroxinectin was obtained from the haemocytes of Indian white shrimp Fenneropenaeus indicus using RT-PCR and RACE. Fenneropenaeus indicus peroxinectin (Fi-Pxn) sequence has an open reading frame (ORF) of 2415 bp encoding a protein of 804 amino acids with 21 residues signal sequence. The mature protein has molecular mass of 89.8 kDa with an estimated pI of 8.6. Two putative integrin-binding motifs, RGD and KGD, were observed at the basic N-terminal and C-terminal part of the mature aminoacid sequence. Fi-Pxn nucleotide sequence comparison showed high homology to mud crab Scylla serrata (89%) and to various vertebrate and invertebrate species. qRT-PCR showed peroxinectin mRNA transcript in haemocytes of F. indicus increased at 6 h post injection of peptidoglycan and Vibrio harveyi. The Fi-Pxn was mainly expressed in the tissues of haemocytes and the heart. The moulting stage responses showed Fi-Pxn expression in premoult stages D0/1 and D0/2.