The control of the cell cycle in early sea urchin and starfish embryos will be studied in terms of nucleo-cytoplasmic interactions. Aphidicolin, a recently discovered drug which inhibits DNA replication specifically, will be applied to early embryos in connection with the recently developed technique of egg fusion. This experimental approach is designed to make several new determinations about cell cycle control in the early embryo: (1) whether or not the unreplicated nucleus exerts negative control over progression through the cell cycle; (2) whether or not the cytoplasm of the replicated cell can exert positive control over the unreplicated nucleus; and (3) whether or not any controlling factors inferred from these studies can cross taxonomic class barriers between sea urchins and starfish. Additional new determinations about necleocytoplasmic interactions in unfertilized eggs and immature oocytes using the egg fusion technique only include: (4) whether or not nuclear DNA replication is stimulated in an unfertilized sea urchin egg upon fusion with a fertilized egg; (5) whether or not germinal vesicle breakdown and maturation of an immature sea urchin oocyte is stimulated upon fusion with an unfertilized egg; (6) whether or not germinal vesicle breakdown and maturation of an immature starfish oocyte is stimulated upon fusion with a mature starfish oocyte; and (7) whether or not any controlling factors inferred from these studies can cross taxonomic class barriers between sea urchins and starfish. These determinations should provide a more complete understanding of how the nucleus and cytoplasm are related with one another during the production of the egg and through early cleavage of the embryo.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD019054-03
Application #
3316224
Study Section
Reproductive Biology Study Section (REB)
Project Start
1984-12-01
Project End
1989-08-31
Budget Start
1987-12-01
Budget End
1989-08-31
Support Year
3
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Georgetown University
Department
Type
Schools of Arts and Sciences
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
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Vafa, O; Nishioka, D (1995) Developmentally regulated protease expression during sea urchin embryogenesis. Mol Reprod Dev 40:36-47
Ward, R D; Mendoza, L M; Moy, G W et al. (1994) A unique expression pattern for a sperm membrane protein during sea urchin spermatogenesis. Zygote 2:159-65
Ward, R D; Nishioka, D (1993) Seasonal changes in testicular structure and localization of a sperm surface glycoprotein during spermatogenesis in sea urchins. J Histochem Cytochem 41:423-31
Mendoza, L M; Nishioka, D; Vacquier, V D (1993) A GPI-anchored sea urchin sperm membrane protein containing EGF domains is related to human uromodulin. J Cell Biol 121:1291-7
Shen, R L; Ward, R D; Pinto da Silva, P et al. (1991) Localization of wheat germ agglutinin and antibody binding sites on the plasma membranes of sea urchin sperm heads as revealed by label-fracture and fracture-flip. Mol Reprod Dev 28:410-8
Nishioka, D; Ward, R D; Poccia, D et al. (1990) Localization of bindin expression during sea urchin spermatogenesis. Mol Reprod Dev 27:181-90
Cameron, R A; Minor, J E; Nishioka, D et al. (1990) Locale and level of bindin mRNA in maturing testis of the sea urchin, Strongylocentrotus purpuratus. Dev Biol 142:44-9
Nishioka, D; Gorman, E A; Ward, R D (1989) Changing localizations of site-specific sperm surface antigens during sea urchin fertilization. J Exp Zool 251:74-81
Semancik, G J; Shust, N M; Byrnes, S A et al. (1988) Induction of the cortical reaction in isolated sea urchin egg cortices: effects of Ca2+ and ionophore A23187. Cell Biol Int Rep 12:857-66

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