“SYNTHESIS, DISTRIBUTION AND LEVELS OF PERIVITELLIN-2 AN EGG LIPOPROTEIN FROM THE APPLE SNAIL POMACEA CANALICULATA (MOLLUSCA: GASTROPODA)”

DREON, M.; LAVARIAS, SABRINA MARIA LUISA; GARIN, C.F.; HERAS H.; POLLERO R.J

JOURNAL OF EXPERIMENTAL ZOOLOGY

Wiley-Liss

Año: 2002 vol. 292 p. 232 - 330

0022-104X

The site of synthesis of mollusc lipoproteins is hitherto unknown and was investigated for perivitellin 2 (PV2), an egg lipoprotein found in the freshwater snail Pomacea canaliculata. Tissues (albumen gland, gonad-hepatopancreas complex and muscle) from vitellogenic females were incubated in vitro with 14C leucine at 25 C for 12h. At the end of incubation, soluble proteins from tissue homogenates and medium were analyzed for de novo protein synthesis by electrophoresis and HPLC, and radiolabelled proteins were quantified by liquid scintillation. Two albumen gland radiolabelled proteins (67 and 31 kDa) comigrated with the subunits of PV2, and they represented 6.0 % of the total labelled protein in that tissue. Western blot analysis confirmed the presence of PV2 only in the albumen gland. In vivo experiments where adult females were injected with 3H Leucine revealed that PV2 was not present in hemolymph. ELISA analysis in all tissues of the snail confirmed the PV2 presence only in the albumen gland and developing eggs with levels of 26 mg/g and 98 mg/g protein, respectively. Therefore, the albumen gland is the only site for PV2 synthesis, and no extragland synthesis, circulation or accumulation could be found. PV2 subunits were further characterised analysing N-terminal sequences which showed no homology with other proteins.