Regulation of membrane fusion and secretory events in the sea urchin embryo

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5475989

Roe, J L

Membrane fusion and secretory events play a key role in fertilization and early development in the sea urchin embryo. To investigate the mechanism of membrane fusion, the effect of inhibitors of metalloendoprotease activity was studied on two model systems of cell fusion; fertilization and spiculogenesis by primary mesenchyme cells in the embryo. Both the zinc chelator, 1,10-phenanthroline, and peptide metalloprotease substrates were found to inhibit both fertilization and gamete fusion, while peptides that are not substrates of metalloproteases did not affect either process. Primary mesenchyme cells form the larval skeleton in the embryo by deposition of mineral and an organic matrix into a syncytial cavity formed by fusion of filopodia of these cells. Metalloprotease inhibitors were found to inhibit spiculogenesis both in vivo and in cultures of isolated primary mesenchyme cells, and the activity of a metalloprotease of the appropriate specificity was found in the primary mesenchyme cells. These two studies implicate the activity of a metalloprotease in a necessary step in membrane fusion. Following fertilization, exocytosis of the cortical granules results in the formation of the fertilization envelope and the hyaline layer, that surround the developing embryo. The hatching enzyme is secreted by the blastula stage sea urchin embryo, which proteolyzes the fertilization envelope surrounding the embryo, allowing the embryo to hatch. Using an assay that measures {sup 125}I-fertilization envelope degradation, the hatching enzyme was identified as a 33 kDa metalloprotease, and was purified by ion-exchange and affinity chromatography from the hatching media of Strongylocentrotus purpuratus embryos. The hatching enzyme showed a substrate preference for only a minor subset of fertilization envelope proteins.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• OSTI ID: 5475989
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CELL CONSTITUENTS
CELL MEMBRANES
CHELATING AGENTS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
ECHINODERMS
ELECTRON CAPTURE RADIOISOTOPES
EMBRYOS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
FERTILIZATION
HYDROLASES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
INVERTEBRATES
IODINE 125
IODINE ISOTOPES
ION EXCHANGE CHROMATOGRAPHY
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ONTOGENESIS
PEPTIDE HYDROLASES
RADIOISOTOPES
REACTION KINETICS
SEA URCHINS
SEPARATION PROCESSES
TRACER TECHNIQUES