Molecular cloning, characterization and expression analysis of thrombospondin gene from Penaeus monodon

In present study, a thrombospondin gene was obtained from the ovary and neurosecretory organ in eyestalk cDNA library of black tiger prawn (Penaeus monodon). The full-length P. monodon thrombospondin (PmTSP) cDNA contained a 5' untranslated region (UTR) of 9 bp, an open reading frame (ORF) of 2778 bp encoding a polypeptide of 925 amino acids with molecular mass 100.57 kDa, and a 3'UTR of 99 bp. ScanProsite analysis indicated that PmTSP contained four chitin-binding type-II domains, an EGF-like domain, eight thrombospondin type-III repeats and one thrombospondin C-terminal domain. Homology analysis of the deduced amino acid sequence of the PmTSP with other known TSP sequences by MatGAT software revealed that the PmTSP shows very high homology with the sequences of Fennerpenaeus chinensis (89.9% similarity, 83.8% identity). Analysis of the tissue expression pattern of the PmTSP gene showed that the PmTSP mRNA was expressed in all tested tissues, including hepatopancreas, ovary, muscle, intestine, neurosecretory organ in eyestalk, neurosecretory organ in brain, stomach, and heart, with highest level in the ovary. Furthermore, the PmTSP expression was found to be of high level in six development stages of the ovary. The results indicated that PmTSP might play an important role in ovarian development.