The Israeli Journal of Aquaculture - Bamidgeh 55(4), 2003
The 7th Annual Dan Popper Symposium


MOLECULAR CHARACTERIZATION AND GENE EXPRESSION
OF TWO PROTEINS FROM PENAEID SHRIMP (PENAEUS
SEMISULCATUS) OVARIES DURING OOCYTE DEVELOPMENT


J.-C. Avarre¹**, M. Khayat¹***, P. Babin², R. Michelis¹***, H. Nagasawa³, A.Tietz 4 and E.Lubzens¹*

1 Israel Oceanographic and Limnological Research, P.O. Box 8030, Haifa 31080, Israel

2 Genomique et Physiologie des Poissons USC INRA, Universite Bordeaux 1 33405 Talence Cedex, France

3 Department of Applied Biological Chemistry, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan

4 Department of Neurobiochemistry, Tel Aviv University, Tel Aviv 66978, Israel


Abstract

Two proteins contained in the ovaries of penaeid shrimps have been identified so far: vitel-logenin/ vitellin (VT/VTG), the main protein component of egg yolk, and shrimp ovarian peritrophin protein (SOP), a component of the cortical rods and jelly layer formed around the eggs immediately after spawning. The cDNAs encoding of VT/VTG and SOP were cloned and sequenced in Penaeus semisulcatus.

VT/VTG transcripts (~8 kb) were detected in the ovary and hepatopancreas and their level of expression was related to the stage of ovarian development and molt cycle. Although they are of the same length (2569 amino acids), VT from the ovary and VTG from the plasma were composed of three and two subunits, respectively. Cleavage occurred at a consensus motif for a subtilisin-like convertase in VT and VTG, and an additional cleavage occurred only in VT, by an unidentified endoprotease. Phylogenetic analysis indicated that crustacean VTGs are more closely related to insect apolipophorins and vertebrate apolipoprotein B-100, suggesting a possible role in the endogenous lipid transport pathway.

SOP mRNA (~1 kb) was expressed in the ovaries at all oocyte developmental stages, where-as expression in the hepatopancreas was restricted to vitellogenic stages. SOP mRNA was abundant in the ovary and detected in previtellogenic stages before the occurrence of the corresponding protein. SOP showed the presence of repeated cysteine-rich domains, was glycosylated and could bind chitin when extracted from cortical rods. It shares these properties with insect intestinal peritrophins and mucins, crustacean tachycitin and invertebrate chitinases.

*Corresponding author. E-mail: esther@ocean.org.il
**Present address: DRIM, IFREMER/CNRS, 2 Place E.Bataillon, CP 80, 34095 Montpellier Cedex 5, France
***Present address: Eliachar Research Laboratory, Western Galilee Hospital, Nahariya 22100, Israel


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