Molecular Characterization and High Expression During Oocyte Development of a Shrimp Ovarian Cortical Rod Protein Homologous to Insect Intestinal Peritrophins1

Abstract

Penaeoid shrimp oocytes nearing the completion of oogenesis are enveloped in an acellular vitelline envelope and possess extracellular cortical rods (CRs) that extended into the cortical cytoplasm. These cortical specializations are precursors of the jelly layer (JL) of the egg. In searching for highly expressed mRNAs during oogenesis in the marine shrimp (Penaeus semisulcatus), two related cDNAs have been isolated that encode a mature protein of 250 amino acid residues. The deduced amino acid sequences revealed the presence of repeated cysteine-rich domains that are related to the chitin-binding domains of insect intestinal peritrophins. Similar cysteine-rich domains were reported in insect intestinal mucin, crustacean tachycitin, and invertebrate chitinases. The shrimp ovarian peritrophin (SOP) is glycosylated and can bind chitin when extracted from CRs. Its apparent molecular mass in SDS-PAGE is 29-35 kDa and 33-36 kDa, under nonreducing or reducing conditions, respectively. SOP is a major protein of CRs and the JL, and was immunodetected in ovaries; purified CRs; fertilized eggs that were surrounded by a JL matrix; and in the cloudy, whitish flocculent material appearing in sea water immediately after spawning. Immunolocalization in tissue sections determined that SOP was present in oocyte cytoplasm and in extraoocytic CRs. Shrimp expressed SOP mRNA in ovaries at all oocyte developmental stages, whereas expression in the hepatopancreas was restricted to vitellogenic stages. SOP mRNA was abundant in the shrimp ovary and was detected before the presence of the corresponding protein. This is the first demonstration that a protein with similar features to insect intestinal peritrophins is a component of CRs and is therefore a main precursor of the JL of spawned shrimp eggs.

Molecular Cloning and Ovarian Expression Profiles of Thrombospondin, a Major Component of Cortical Rods in Mature Oocytes of Penaeid Shrimp, Marsupenaeus japonicus1

“…This domain was rich in cysteine, and the position was completely conserved in mjTSP and SOPs. The positions of N-terminus in mature proteins demonstrated by peptide sequencing were also conserved between mjTSP and SOP [3].…”

“…Two related cDNA sequences encode CR proteins with a molecular mass of about 30 kDa in Penaeus semisulcatus [3]. Given a sequence homology to insect intestinal peritrophin, the CR proteins were designated shrimp ovarian peritrophin (SOP)1 and SOP2.…”

Glucosamine: fructose-6-phosphate amidotransferase in the white shrimp Litopenaeus vannamei: characterization and regulation under alkaline and cadmium stress

“…GFAT may have separate functions in different anatomical locations, as was reported by Huang et al (2007) in the H. longicornis (ixodid tick). The intestinal peritrophins of insect was thought to be chitin-binding domains (Khayat et al 2001). The same speculation could be applied to the shrimp.…”

Reproductive Mechanisms in Crustacea Focusing on Selected Prawn Species: Vitellogenin Structure, Processing and Synthetic Control

“…Two major proteins comprising the cortical rods have been purified and characterized: shrimp ovarian peritrophin (SOP, 29-35 and 33-36 kDa) in Penaeus semisulcatus (Khayat et al 2001) or cortical rod protein (CRP, 28.6 and 30.5 kDa) in Mar. japonicus (Kim et al 2004(Kim et al , 2005; and Mar.…”

“…Messenger RNAs for SOP, CRP, and MjTSP are expressed in the previtellogenic oocytes, and the respective proteins are synthesized and accumulated in the vitellogenic oocytes as yolk materials (Khayat et al 2001;Yamano et al 2003Yamano et al , 2004Kim et al 2004Kim et al , 2005. The proteins are first scattered throughout the ooplasm, and then become localized in the cortical rods during cortical rod formation.…”