Abstract
Drosophila melanogaster mature oocytes in ovaries are arrested at metaphase I of meiosis. Eggs that have reached the uterus have released this arrest. It was not known where in the female reproductive tract egg activation occurs and what triggers it. We investigated when and where the egg is activated in Drosophila in vivo and at what meiotic stage the egg is fertilized. We found that changes in the egg's envelope's permeability, one feature of activation, initiate during ovulation, even while most of the egg is still within the ovary. The egg becomes impermeable as it proceeds down the oviducts; the process is complete by the time the egg is in the uterus. Cross-linking of vitelline membrane protein sV23 also increases progressively as the egg moves through the oviducts and the uterus. Activation also triggers meiosis to resume before the egg reaches the uterus, such that the earliest eggs that reach the uterus are in anaphase I. We discuss models for Drosophila egg activation in vivo.
| Original language | English |
|---|---|
| Pages (from-to) | 416-424 |
| Number of pages | 9 |
| Journal | Developmental Biology |
| Volume | 234 |
| Issue number | 2 |
| DOIs | |
| State | Published - 15 Jun 2001 |
| Externally published | Yes |
Bibliographical note
Funding Information:We thank Dr. S. Pitnick for advice on detecting Drosophila sperm tails, Dr. S. Endow for ncd-gfp* flies, Drs. G. Schubiger, T. Kaufman, and L. Salkoff for helpful discussion of the role of mechanical cues for activation, Drs. E. LeMosy and C. Hashimoto for anti-sV23 (from G. Waring, whom we also thank) and helpful discussion of vitelline membrane cross-linking, and Drs. K. Kem-phues, R. Cerione, and S. Mani and anonymous reviewers for helpful comments on the manuscript. This work was supported by grants to M.F.W. from NIH (GM44659) and NSF (IBN99-04824).
Keywords
- Activation
- Cross-linking
- Drosophila
- Fertilization
- Meiosis
- Ovulation
- Vitelline membrane
- Vitelline membrane proteins