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Watabe M, Hiraiwa A, Sakai M, Ueno T, Ueno S, Nakajima K, Yaoita Y, Iwao Y. Sperm MMP-2 is indispensable for fast electrical block to polyspermy at fertilization in Xenopus tropicalis. Mol Reprod Dev 2021; 88:744-757. [PMID: 34618381 DOI: 10.1002/mrd.23540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 09/24/2021] [Indexed: 01/10/2023]
Abstract
Sperm matrix metalloproteinase-2 (MMP-2) is necessary for frog fertilization. Monospermy is ensured by a fast, electrical block to polyspermy mediated by a positive fertilization potential. To determine the role of the MMP-2 hemopexin domain (HPX) in a fast block to polyspermy during fertilization of the frog, Xenopus tropicalis, we prepared mutant frogs deficient in mmp2 gene using the transcription activator-like effector nuclease method. mmp2 ΔHPX (-/-) sperm without MMP-2 protein were able to fertilize wild-type (WT; +/+) eggs. However, polyspermy occurred in some eggs. The mutant sperm generated a normal fertilization potential amounting to 10 mV, and were able to fertilize eggs at 10 mV, at which WT sperm never fertilized. Sensitivity during voltage-dependent fertilization decreased in mutant sperm. This study demonstrates for the first time that the genetic alteration of the MMP-2 molecule in sperm causes polyspermy during fertilization of a monospermic species. Our findings provide reliable evidence that sperm MMP-2 is indispensable for the fast, electrical block to polyspermy during Xenopus fertilization.
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Affiliation(s)
- Mami Watabe
- Laboratory of Reproductive Developmental Biology and Developmental Cell Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Azusa Hiraiwa
- Laboratory of Reproductive Developmental Biology and Developmental Cell Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Mami Sakai
- Laboratory of Reproductive Developmental Biology and Developmental Cell Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Tomoyo Ueno
- Laboratory of Reproductive Developmental Biology and Developmental Cell Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Shuichi Ueno
- Laboratory of Reproductive Developmental Biology and Developmental Cell Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Keisuke Nakajima
- Division of Embryology, Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
| | - Yoshio Yaoita
- Division of Embryology, Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
| | - Yasuhiro Iwao
- Laboratory of Reproductive Developmental Biology and Developmental Cell Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
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