Zinc is an intracellular signal during sperm activation in <i>Caenorhabditis elegans</i>
Creators
Abstract
Sperm activation is a rapid and dramatic cell differentiation event that does not involve changes in transcription, and the signaling cascades that mediate this process have not been fully defined. zipt-7.1 encodes a zinc transporter, and zipt-7.1(lf) mutants display sperm-activation defects, leading to the hypothesis that zinc signaling mediates sperm activation in Caenorhabditis elegans. Here, we describe the development of a method for dynamic imaging of labile zinc during sperm activation using the zinc-specific fluorescence probe FluoZin-3 AM and time-lapse confocal imaging. Two phases of dynamic changes in labile zinc levels were observed during sperm activation. Forced zinc entry using the zinc ionophore pyrithione activated sperm in vitro, and it suppressed the defects of zipt-7.1(lf) mutants, indicating that high levels of cytosolic zinc are sufficient for sperm activation. We compared activation by zinc pyrithione to activation by extracellular zinc, the Na⁺/H⁺ antiporter monensin and the protease cocktail pronase in multiple mutant backgrounds. These results indicate that the protease pathway does not require zinc signaling, suggesting that zinc signaling is sufficient to activate sperm but is not always necessary.
Copyright and License
© 2021. Published by The Company of Biologists.
Acknowledgement
We thank Mike Shih and the Washington University Center for Cellular Imaging (WUCCI) for microscopy assistance. We thank Zuzana Kocsisova, David Piston, Tim Schedl and members of the Schedl lab (Washington University in St. Louis), and Gillian Stanfield and Kristin Fenker (University of Utah) for technical assistance. Some stains were obtained from the Caenorhabditis Genetics Center (CGC), which is funded by the NIH Office of Research Infrastructure Programs (P40 OD010440).
Funding
This research was funded by a National Institutes of Health award (R01 GM068598 to K.K.). C.-H.T. was a scholar of the McDonnell International Scholars Academy. Deposited in PMC for release after 12 months.
Contributions
Conceptualization: C.-H.T., K.K.; Methodology: C.-H.T.; Validation: C.-H.T.; Formal analysis: C.-H.T.; Investigation: C.-H.T.; Resources: K.K.; Data curation: C.-H.T.; Writing - original draft: C.-H.T., K.K.; Writing - review & editing: C.-H.T., K.K.; Visualization: C.-H.T.; Supervision: K.K.; Funding acquisition: C.-H.T., K.K.
Conflict of Interest
The authors declare no competing or financial interests.
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Additional details
Identifiers
- ISSN
- 1477-9129
- PMCID
- PMC8602944
Funding
- National Institutes of Health
- R01 GM068598
- McDonnell International Scholars Academy