Abstract
Sperm activation is a fascinating example of cell differentiation, in which immotile spermatids undergo a rapid and dramatic transition to become mature, motile sperm. Because the sperm nucleus is transcriptionally silent, this transition does not involve transcriptional changes. Although Caenorhabditis elegans is a leading model for studies of sperm activation, the mechanisms by which signaling pathways induce this transformation remain poorly characterized. Here we show that a conserved transmembrane zinc transporter, ZIPT-7.1, regulates the induction of sperm activation in Caenorhabditis nematodes. The zipt-7.1 mutant hermaphrodites cannot self-fertilize, and males reproduce poorly, because mutant spermatids are defective in responding to activating signals. The zipt-7.1 gene is expressed in the germ line and functions in germ cells to promote sperm activation. When expressed in mammalian cells, ZIPT-7.1 mediates zinc transport with high specificity and is predominantly located on internal membranes. Finally, genetic epistasis places zipt-7.1 at the end of the spe-8 sperm activation pathway, and ZIPT-7.1 binds SPE-4, a presenilin that regulates sperm activation. Based on these results, we propose a new model for sperm activation. In spermatids, inactive ZIPT-7.1 is localized to the membranous organelles, which contain higher levels of zinc than the cytoplasm. When sperm activation is triggered, ZIPT-7.1 activity increases, releasing zinc from internal stores. The resulting increase in cytoplasmic zinc promotes the phenotypic changes characteristic of activation. Thus, zinc signaling is a key step in the signal transduction process that mediates sperm activation, and we have identified a zinc transporter that is central to this activation process.
Recommended Citation
Y. Zhao and C. H. Tan and A. Krauchunas and A. Scharf and N. Dietrich and K. Warnhoff and Z. Yuan and M. Druzhinina and S. G. Gu and L. Miao and A. Singson and R. E. Ellis and K. Kornfeld, "The Zinc Transporter ZIPT-7.1 Regulates Sperm Activation In Nematodes," PLoS Biology, vol. 16, no. 6, article no. e2005069, Public Library of Science, Jun 2018.
The definitive version is available at https://doi.org/10.1371/journal.pbio.2005069
Department(s)
Biological Sciences
Publication Status
Open Access
International Standard Serial Number (ISSN)
1545-7885; 1544-9173
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2023 The Authors, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
01 Jun 2018
PubMed ID
29879108
Comments
National Science Foundation, Grant 1021128