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Guo J, Zhao H, Zhang J, Lv X, Zhang S, Su R, Zheng W, Dai J, Meng F, Gong F, Lu G, Xue Y, Lin G. Selective Translation of Maternal mRNA by eIF4E1B Controls Oocyte to Embryo Transition. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205500. [PMID: 36755190 PMCID: PMC10104655 DOI: 10.1002/advs.202205500] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Maternal messenger ribonucleic acids (mRNAs) are driven by a highly orchestrated scheme of recruitment to polysomes and translational activation. However, selecting and regulating individual mRNAs for the translation from a competitive pool of mRNAs are little-known processes. This research shows that the maternal eukaryotic translation initiation factor 4e1b (Eif4e1b) expresses during the oocyte-to-embryo transition (OET), and maternal deletion of Eif4e1b leads to multiple defects concerning oogenesis and embryonic developmental competence during OET. The linear amplification of complementary deoxyribonucleic acid (cDNA) ends, and sequencing (LACE-seq) is used to identify the distinct subset of mRNA and its CG-rich binding sites within the 5' untranslated region (UTR) targeted by eIF4E1B. The proteomics analyses indicate that eIF4E1B-specific bound genes show stronger downregulation at the protein level, which further verify a group of proteins that plays a crucial role in oocyte maturation and embryonic developmental competence is insufficiently synthesized in Eif4e1b-cKO oocytes during OET. Moreover, the biochemical results in vitro are combined to further confirm the maternal-specific translation activation model assembled by eIF4E1B and 3'UTR-associated mRNA binding proteins. The findings demonstrate the indispensability of eIF4E1B for selective translation activation in mammalian oocytes and provide a potential network regulated by eIF4E1B in OET.
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Affiliation(s)
- Jing Guo
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
| | - Hailian Zhao
- Key Laboratory of RNA BiologyInstitute of BiophysicsChinese Academy of SciencesBeijing100101P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Jue Zhang
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
| | - Xiangjiang Lv
- Laboratory of Reproductive and Stem Cell EngineeringNHC Key Laboratory of Human Stem Cell and Reproductive EngineeringCentral South UniversityChangsha410078P. R. China
| | - Shen Zhang
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
| | - Ruibao Su
- Key Laboratory of RNA BiologyInstitute of BiophysicsChinese Academy of SciencesBeijing100101P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Wei Zheng
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
| | - Jing Dai
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
- Laboratory of Reproductive and Stem Cell EngineeringNHC Key Laboratory of Human Stem Cell and Reproductive EngineeringCentral South UniversityChangsha410078P. R. China
| | - Fei Meng
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
| | - Fei Gong
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
- Laboratory of Reproductive and Stem Cell EngineeringNHC Key Laboratory of Human Stem Cell and Reproductive EngineeringCentral South UniversityChangsha410078P. R. China
| | - Guangxiu Lu
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
- Laboratory of Reproductive and Stem Cell EngineeringNHC Key Laboratory of Human Stem Cell and Reproductive EngineeringCentral South UniversityChangsha410078P. R. China
| | - Yuanchao Xue
- Key Laboratory of RNA BiologyInstitute of BiophysicsChinese Academy of SciencesBeijing100101P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Ge Lin
- Clinical Research Center for Reproduction and Genetics in Hunan ProvinceReproductive and Genetic Hospital of CITIC‐XiangyaChangsha410078P. R. China
- Laboratory of Reproductive and Stem Cell EngineeringNHC Key Laboratory of Human Stem Cell and Reproductive EngineeringCentral South UniversityChangsha410078P. R. China
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Zhang S, Gong X, Zhou Y, Ma Q, Cai Q, Yang G, Guo X, Chen Y, Xu M, Zhu Y, Zeng Y, Zeng F. Maternal Prkce expression in mature oocytes is critical for the first cleavage facilitating maternal-to-zygotic transition in mouse early embryos. Cell Prolif 2022; 55:e13231. [PMID: 35582855 PMCID: PMC9201378 DOI: 10.1111/cpr.13231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/17/2022] [Accepted: 03/23/2022] [Indexed: 11/27/2022] Open
Abstract
Objectives Early embryo development is dependent on the regulation of maternal messages stored in the oocytes during the maternal‐to‐zygote transition. Previous studies reported variability of oocyte competence among different inbred mouse strains. The present study aimed to identify the maternal transcripts responsible for early embryonic development by comparing transcriptomes from oocytes of high‐ or low‐ competence mouse strains. Materials and Methods In vitro fertilization embryos from oocytes of different mouse strains were subject to analysis using microarrays, RNA sequencing, real‐time quantitative PCR (RT‐qPCR) analysis, Western blotting, and immunofluorescence. One candidate gene, Prkce, was analysed using Prkce knockout mice, followed by a cRNA rescue experiment. Results The fertilization and 2‐cell rate were significantly higher for FVB/NJ (85.1% and 82.0%) and DBA/2J (79.6% and 76.7%) inbred mouse strains than those for the MRL/lpr (39.9% and 35.8%) and 129S3 (35.9% and 36.6%) strains. Thirty‐nine differentially expressed genes (DEGs) were noted, of which nine were further verified by RT‐qPCR. Prkce knockout mice showed a reduced 2‐cell rate (Prkce+/+ 80.1% vs. Prkce−/− 32.4%) that could be rescued by Prkce cRNA injection (2‐cell rate reached 76.7%). Global transcriptional analysis revealed 143 DEGs in the knockout mice, which were largely composed of genes functioning in cell cycle regulation. Conclusions The transcription level of maternal messages such as Prkce in mature oocytes is associated with different 2‐cell rates in select inbred mouse strains. Prkce transcript levels could serve as a potential biomarker to characterize high‐quality mature oocytes.
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Affiliation(s)
- Shaoqing Zhang
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiuli Gong
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yiye Zhou
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,Department of Histo-Embryology, Genetics and Developmental Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Qingwen Ma
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Qin Cai
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Guanheng Yang
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Xinbing Guo
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Yanwen Chen
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Miao Xu
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Yiwen Zhu
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Yitao Zeng
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Fanyi Zeng
- School of Life Sciences and Biotechnology & Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.,Department of Histo-Embryology, Genetics and Developmental Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China.,School of Pharmacy, Macau University of Science and Technonlogy, Taipa, Macau, China
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3
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Ge Q, Guo Y, Zheng W, Cai Y, Qi X, Zhao S. A comparative analysis of differentially expressed mRNAs, miRNAs and circRNAs provides insights into the key genes involved in the high-altitude adaptation of yaks. BMC Genomics 2021; 22:744. [PMID: 34654374 PMCID: PMC8518315 DOI: 10.1186/s12864-021-08044-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 09/29/2021] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Yaks that inhabit the Tibetan Plateau exhibit striking phenotypic and physiological differences from cattle and have adapted well to the extreme conditions on the plateau. However, the mechanisms used by these animals for the regulation of gene expression at high altitude are not fully understood. RESULTS Here, we sequenced nine lung transcriptomes of yaks at altitudes of 3400, 4200 and 5000 m, and low-altitude Zaosheng cattle, which is a closely related species, served as controls. The analysis identified 21,764 mRNAs, 1377 circRNAs and 1209 miRNAs. By comparing yaks and cattle, 4975 mRNAs, 252 circRNAs and 75 miRNAs were identified differentially expressed. By comparing yaks at different altitudes, we identified 756 mRNAs, 64 circRNAs and 83 miRNAs that were differentially expressed (fold change ≥2 and P-value < 0.05). The pathways enriched in the mRNAs, circRNAs and miRNAs identified from the comparison of yaks and cattle were mainly associated with metabolism, including 'glycosaminoglycan degradation', 'pentose and glucuronate interconversions' and 'flavone and flavonol biosynthesis', and the mRNAs, circRNAs and miRNAs identified from the comparison of yaks at different altitude gradients were significantly enriched in metabolic pathways and immune and genetic information processing pathways. The core RNAs were identified from the mRNA-miRNA-circRNA networks constructed using the predominant differentially expressed RNAs. The core genes specific to the difference between yaks and cattle were associated with the endoplasmic reticulum and fat deposition, but those identified from the comparison among yaks at different altitude gradients were associated with maintenance of the normal biological functions of cells. CONCLUSIONS This study enhances our understanding of the molecular mechanisms involved in hypoxic adaptation in yaks and might contribute to improvements in the understanding and prevention of hypoxia-related diseases.
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Affiliation(s)
- Qianyun Ge
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Yongbo Guo
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Wangshan Zheng
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Yuan Cai
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Xuebin Qi
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Shengguo Zhao
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China.
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4
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Chen L, Kashina A. Post-translational Modifications of the Protein Termini. Front Cell Dev Biol 2021; 9:719590. [PMID: 34395449 PMCID: PMC8358657 DOI: 10.3389/fcell.2021.719590] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/30/2021] [Indexed: 12/12/2022] Open
Abstract
Post-translational modifications (PTM) involve enzyme-mediated covalent addition of functional groups to proteins during or after synthesis. These modifications greatly increase biological complexity and are responsible for orders of magnitude change between the variety of proteins encoded in the genome and the variety of their biological functions. Many of these modifications occur at the protein termini, which contain reactive amino- and carboxy-groups of the polypeptide chain and often are pre-primed through the actions of cellular machinery to expose highly reactive residues. Such modifications have been known for decades, but only a few of them have been functionally characterized. The vast majority of eukaryotic proteins are N- and C-terminally modified by acetylation, arginylation, tyrosination, lipidation, and many others. Post-translational modifications of the protein termini have been linked to different normal and disease-related processes and constitute a rapidly emerging area of biological regulation. Here we highlight recent progress in our understanding of post-translational modifications of the protein termini and outline the role that these modifications play in vivo.
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Affiliation(s)
| | - Anna Kashina
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
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5
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Efthymiou S, Dutra-Clarke M, Maroofian R, Kaiyrzhanov R, Scala M, Reza Alvi J, Sultan T, Christoforou M, Tuyet Mai Nguyen T, Mankad K, Vona B, Rad A, Striano P, Salpietro V, Guillen Sacoto MJ, Zaki MS, Gleeson JG, Campeau PM, Russell BE, Houlden H. Expanding the phenotype of PIGS-associated early onset epileptic developmental encephalopathy. Epilepsia 2021; 62:e35-e41. [PMID: 33410539 PMCID: PMC7898547 DOI: 10.1111/epi.16801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 12/13/2022]
Abstract
The phosphatidylinositol glycan anchor biosynthesis class S protein (PIGS) gene has recently been implicated in a novel congenital disorder of glycosylation resulting in autosomal recessive inherited glycosylphosphatidylinositol-anchored protein (GPI-AP) deficiency. Previous studies described seven patients with biallelic variants in the PIGS gene, of whom two presented with fetal akinesia and five with global developmental delay and epileptic developmental encephalopathy. We present the molecular and clinical characteristics of six additional individuals from five families with unreported variants in PIGS. All individuals presented with hypotonia, severe global developmental delay, microcephaly, intractable early infantile epilepsy, and structural brain abnormalities. Additional findings include vision impairment, hearing loss, renal malformation, and hypotonic facial appearances with minor dysmorphic features but without a distinctive facial gestalt. Four individuals died due to neurologic complications. GPI anchoring studies performed on one individual revealed a significant decrease in GPI-APs. We confirm that biallelic variants in PIGS cause vitamin pyridoxine-responsive epilepsy due to inherited GPI deficiency and expand the genotype and phenotype of PIGS-related disorder. Further delineation of the molecular spectrum of PIGS-related disorders would improve management, help develop treatments, and encourage the expansion of diagnostic genetic testing to include this gene as a potential cause of neurodevelopmental disorders and epilepsy.
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Affiliation(s)
- Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Marina Dutra-Clarke
- Department of Pediatrics, Division of Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Reza Maroofian
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Rauan Kaiyrzhanov
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Marcello Scala
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Javeria Reza Alvi
- Department of Pediatric Neurology, Institute of Child Health, Children's Hospital Lahore, Lahore, Pakistan
| | - Tipu Sultan
- Department of Pediatric Neurology, Institute of Child Health, Children's Hospital Lahore, Lahore, Pakistan
| | - Marilena Christoforou
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Thi Tuyet Mai Nguyen
- Research Center, Saint Justine University Hospital Center, University of Montreal, Montreal, QC, Canada
| | - Kshitij Mankad
- Department of Neuroradiology, Great Ormond Street Hospital for Children, London, UK
| | - Barbara Vona
- Department of Otolaryngology-Head and Neck Surgery, Tübingen Hearing Research Center, Eberhard Karls University, Tübingen, Germany
| | - Aboulfazl Rad
- Department of Otolaryngology-Head and Neck Surgery, Tübingen Hearing Research Center, Eberhard Karls University, Tübingen, Germany
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Vincenzo Salpietro
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | | | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Center, Cairo, Egypt
| | - Joseph G Gleeson
- Department of Neuroscience, Rady Children's Institute for Genomic Medicine, Howard Hughes Medical Institute, University of California, San Diego, San Diego, CA, USA
| | - Philippe M Campeau
- Research Center, Saint Justine University Hospital Center, University of Montreal, Montreal, QC, Canada
| | - Bianca E Russell
- Department of Pediatrics, Division of Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
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Desnoyer N, Palanivelu R. Bridging the GAPs in plant reproduction: a comparison of plant and animal GPI-anchored proteins. PLANT REPRODUCTION 2020; 33:129-142. [PMID: 32945906 DOI: 10.1007/s00497-020-00395-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 09/07/2020] [Indexed: 05/29/2023]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GAPs) are a unique type of membrane-associated proteins in eukaryotes. GPI and GAP biogenesis and function have been well studied in non-plant models and play an important role in the fertility of mouse sperm and egg. Although GPI and GAP biogenesis and function in plants are less known, they are critical for flowering plant reproduction because of their essential roles in the fertility of the male and female gametophytes. In Eukaryotes, GPI, a glycolipid molecule, can be post-translationally attached to proteins to serve as an anchor in the plasma membrane. GPI-anchoring, compared to other modes of membrane attachment and lipidation processes, localizes proteins to the extracellular portion of the plasma membrane and confers several unique attributes including specialized sorting during secretion, molecular painting onto membranes, and enzyme-mediated release of protein through anchor cleavage. While the biosynthesis, structure, and role of GPI are mostly studied in mammals, yeast and protists, the function of GPI and GAPs in plants is being discovered, particularly in gametophyte development and function. Here, we review GPI biosynthesis, protein attachment, and remodeling in plants with insights about this process in mammals. Additionally, we summarize the reproductive phenotypes of all loss of function mutations in Arabidopsis GPI biosynthesis and GAP genes and compare these to the reproductive phenotypes seen in mice to serve as a framework to identify gaps in our understanding of plant GPI and GAPs. In addition, we present an analysis on the gametophyte expression of all Arabidopsis GAPs to assist in further research on the role of GPI and GAPs in all aspects of the gametophyte generation in the life cycle of a plant.
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Affiliation(s)
- Nicholas Desnoyer
- School of Plant Sciences, University of Arizona, Tucson, AZ, 85721, USA
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland
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7
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Inoue N, Saito T, Wada I. Unveiling a novel function of CD9 in surface compartmentalization of oocytes. Development 2020; 147:dev.189985. [PMID: 32665248 DOI: 10.1242/dev.189985] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 07/06/2020] [Indexed: 01/02/2023]
Abstract
Gamete fusion is an indispensable process for bearing offspring. In mammals, sperm IZUMO1-oocyte JUNO recognition essentially carries out the primary step of this process. In oocytes, CD9 is also known to play a crucial role in gamete fusion. In particular, microvilli biogenesis through CD9 involvement appears to be a key event for successful gamete fusion, because CD9-disrupted oocytes produce short and sparse microvillous structures, resulting in almost no fusion ability with spermatozoa. In order to determine how CD9 and JUNO cooperate in gamete fusion, we analyzed the molecular profiles of each molecule in CD9- and JUNO-disrupted oocytes. Consequently, we found that CD9 is crucial for the exclusion of GPI-anchored proteins, such as JUNO and CD55, from the cortical actin cap region, suggesting strict molecular organization of the unique surface of this region. Through distinct surface compartmentalization due to CD9 governing, GPI-anchored proteins are confined to the appropriate fusion site of the oocyte.
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Affiliation(s)
- Naokazu Inoue
- Department of Cell Science, Institute of Biomedical Sciences, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, Fukushima 960-1295, Japan
| | - Takako Saito
- Department of Cell Science, Institute of Biomedical Sciences, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, Fukushima 960-1295, Japan
| | - Ikuo Wada
- Department of Cell Science, Institute of Biomedical Sciences, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, Fukushima 960-1295, Japan
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8
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Li H, You L, Tian Y, Guo J, Fang X, Zhou C, Shi L, Su Y. DPAGT1-Mediated Protein N-Glycosylation Is Indispensable for Oocyte and Follicle Development in Mice. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000531. [PMID: 32714760 PMCID: PMC7375233 DOI: 10.1002/advs.202000531] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/29/2020] [Indexed: 05/11/2023]
Abstract
Post-translational modification of proteins by N-linked glycosylation is crucial for many life processes. However, the exact contribution of N-glycosylation to mammalian female reproduction remains largely undefined. Here, DPAGT1, the enzyme that catalyzes the first step of protein N-glycosylation, is identified to be indispensable for oocyte development in mice. Dpagt1 missense mutation (c. 497A>G; p. Asp166Gly) causes female subfertility without grossly affecting other functions. Mutant females ovulate fewer eggs owing to defective development of growing follicles. Mutant oocytes have a thin and fragile zona pellucida (ZP) due to the reduction in glycosylation of ZP proteins, and display poor developmental competence after fertilization in vitro. Moreover, completion of the first meiosis is accelerated in mutant oocytes, which is coincident with the elevation of aneuploidy. Mechanistically, transcriptomic analysis reveals the downregulation of a number of transcripts essential for oocyte meiotic progression and preimplantation development (e.g., Pttgt1, Esco2, Orc6, and Npm2) in mutant oocytes, which could account for the defects observed. Furthermore, conditional knockout of Dpagt1 in oocytes recapitulates the phenotypes observed in Dpagt1 mutant females, and causes complete infertility. Taken together, these data indicate that protein N-glycosylation in oocytes is essential for female fertility in mammals by specific control of oocyte development.
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Affiliation(s)
- Hui Li
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
| | - Liji You
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
| | - Yufeng Tian
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
| | - Jing Guo
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
| | - Xianbao Fang
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
| | - Chenmin Zhou
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
| | - Lanying Shi
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
| | - You‐Qiang Su
- State Key Laboratory of Reproductive MedicineNanjing Medical UniversityNanjing211166P. R. China
- Women's Hospital of Nanjing Medical UniversityNanjing Maternity and Child Health HospitalNanjing Medical UniversityNanjing211166P. R. China
- Collaborative Innovation Center of Genetics and DevelopmentFudan UniversityShanghai200433P. R. China
- Key Laboratory of Model Animal ResearchNanjing Medical UniversityNanjing211166P. R. China
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9
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Akintayo A, Stanley P. Roles for Golgi Glycans in Oogenesis and Spermatogenesis. Front Cell Dev Biol 2019; 7:98. [PMID: 31231650 PMCID: PMC6566014 DOI: 10.3389/fcell.2019.00098] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 05/21/2019] [Indexed: 12/12/2022] Open
Abstract
Glycosylation of proteins by N- and O-glycans or glycosaminoglycans (GAGs) mostly begins in the endoplasmic reticulum and is further orchestrated in the Golgi compartment via the action of >100 glycosyltransferases that reside in this complex organelle. The synthesis of glycolipids occurs in the Golgi, also by resident glycosyltransferases. A defect in the glycosylation machinery may impair the functions of glycoproteins and other glycosylated molecules, and lead to a congenital disorder of glycosylation (CDG). Spermatogenesis in the male and oogenesis in the female are tightly regulated differentiation events leading to the production of functional gametes. Insights into roles for glycans in gamete production have been obtained from mutant mice following deletion or inactivation of genes that encode a glycosylation activity. In this review, we will summarize the effects of altering the synthesis of N-glycans, O-glycans, proteoglycans, glycophosphatidylinositol (GPI) anchored proteins, and glycolipids during gametogenesis in the mouse. Glycosylation genes whose deletion causes embryonic lethality have been investigated following conditional deletion using various Cre recombinase transgenes with a cell-type specific promoter. The potential effects of mutations in corresponding glycosylation genes of humans will be discussed in relation to consequences to fertility and potential for use in contraception.
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Affiliation(s)
- Ayodele Akintayo
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, United States
| | - Pamela Stanley
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, United States
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10
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Agopiantz M, Xandre-Rodriguez L, Jin B, Urbistondoy G, Ialy-Radio C, Chalbi M, Wolf JP, Ziyyat A, Lefèvre B. Growth arrest specific 1 (Gas1) and glial cell line-derived neurotrophic factor receptor α1 (Gfrα1), two mouse oocyte glycosylphosphatidylinositol-anchored proteins, are involved in fertilisation. Reprod Fertil Dev 2018; 29:824-837. [PMID: 28442042 DOI: 10.1071/rd15367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/10/2015] [Indexed: 12/25/2022] Open
Abstract
Recently, Juno, the oocyte receptor for Izumo1, a male immunoglobulin, was discovered. Juno is an essential glycosylphosphatidylinositol (GIP)-anchored protein. This result did not exclude the participation of other GIP-anchored proteins in this process. After bibliographic and database searches we selected five GIP-anchored proteins (Cpm, Ephrin-A4, Gas1, Gfra1 and Rgmb) as potential oocyte candidates participating in fertilisation. Western blot and immunofluorescence analyses showed that only three were present on the mouse ovulated oocyte membrane and, of these, only two were clearly involved in the fertilisation process, namely growth arrest specific 1 (Gas1) and glial cell line-derived neurotrophic factor receptor α1 (Gfrα1). This was demonstrated by evaluating oocyte fertilisability after treatment of oocytes with antibodies against the selected proteins, with their respective short interference RNA or both. Gfrα1 and Gas1 seem to be neither redundant nor synergistic. In conclusion, oocyte Gas1 and Gfrα1 are both clearly involved in fertilisation.
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Affiliation(s)
- M Agopiantz
- Inserm, U1016, Institut Cochin, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - L Xandre-Rodriguez
- Université Paris Descartes, Sorbonne Paris Cité, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - B Jin
- Université Paris Descartes, Sorbonne Paris Cité, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - G Urbistondoy
- Université Paris Descartes, Sorbonne Paris Cité, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - C Ialy-Radio
- Inserm, U1016, Institut Cochin, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - M Chalbi
- Inserm, U1016, Institut Cochin, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - J-P Wolf
- Service d'Histologie Embryologie Biologie de la Reproduction - CECOS, Hôpital Cochin, AP-HP, F75014 Paris, France
| | - A Ziyyat
- Inserm, U1016, Institut Cochin, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - B Lefèvre
- Inserm, U1016, Institut Cochin, 24 rue du Faubourg Saint-Jacques, 75014, Paris, France
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11
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Sabetian S, Shamsir MS. Deficiency in Sperm-Egg Protein Interaction as a Major Cause of Fertilization Failure. J Membr Biol 2017; 250:133-144. [PMID: 28280854 DOI: 10.1007/s00232-017-9954-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 02/21/2017] [Indexed: 11/29/2022]
Abstract
Complete elucidation of fertilization process at molecular level is one of the unresolved challenges in sexual reproduction studies, and understanding the molecular mechanism is crucial in overcoming difficulties in infertility and unsuccessful in vitro fertilization. Sperm-oocyte interaction is one of the most remarkable events in fertilization process, and deficiency in protein-protein interactions which mediate this interaction is a major cause of unexplained infertility. Due to detection of how the various defects of sperm-oocyte interaction can affect fertilization failure, different experimental methods have been applied. This review summarizes the current understanding of sperm-egg interaction mechanism during fertilization and also accumulates the different types of sperm-egg interaction abnormalities and their association with infertility. Several detection approaches regarding sperm-egg protein interactions and the associated defects are reviewed in this paper.
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Affiliation(s)
- Soudabeh Sabetian
- Department of Biological and Health Sciences, Faculty of Bioscience & Medical Engineering, Universiti Teknologi Malaysia, 81310, Johor, Malaysia.
| | - Mohd Shahir Shamsir
- Department of Biological and Health Sciences, Faculty of Bioscience & Medical Engineering, Universiti Teknologi Malaysia, 81310, Johor, Malaysia.
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12
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Abstract
Fertilization is the culminating event of sexual reproduction, which involves the union of the sperm and egg to form a single, genetically distinct organism. Despite the fundamental role of fertilization, the basic mechanisms involved have remained poorly understood. However, these mechanisms must involve an ordered schedule of cellular recognition events between the sperm and egg to ensure successful fusion. In this article, we review recent progress in our molecular understanding of mammalian fertilization, highlighting the areas in which genetic approaches have been particularly informative and focusing especially on the roles of secreted and cell surface proteins, expressed in a sex-specific manner, that mediate sperm-egg interactions. We discuss how the sperm interacts with the female reproductive tract, zona pellucida, and the oolemma. Finally, we review recent progress made in elucidating the mechanisms that reduce polyspermy and ensure that eggs normally fuse with only a single sperm.
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Affiliation(s)
- Enrica Bianchi
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; ,
| | - Gavin J Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; ,
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13
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Hou Y, Guo X, Cyprys P, Zhang Y, Bleckmann A, Cai L, Huang Q, Luo Y, Gu H, Dresselhaus T, Dong J, Qu LJ. Maternal ENODLs Are Required for Pollen Tube Reception in Arabidopsis. Curr Biol 2016; 26:2343-50. [PMID: 27524487 DOI: 10.1016/j.cub.2016.06.053] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/31/2016] [Accepted: 06/22/2016] [Indexed: 01/02/2023]
Abstract
During the angiosperm (flowering-plant) life cycle, double fertilization represents the hallmark between diploid and haploid generations [1]. The success of double fertilization largely depends on compatible communication between the male gametophyte (pollen tube) and the maternal tissues of the flower, culminating in precise pollen tube guidance to the female gametophyte (embryo sac) and its rupture to release sperm cells. Several important factors involved in the pollen tube reception have been identified recently [2-6], but the underlying signaling pathways are far from being understood. Here, we report that a group of female-specific small proteins, early nodulin-like proteins (ENODLs, or ENs), are required for pollen tube reception. ENs are featured with a plastocyanin-like (PCNL) domain, an arabinogalactan (AG) glycomodule, and a predicted glycosylphosphatidylinositol (GPI) anchor motif. We show that ENs are asymmetrically distributed at the plasma membrane of the synergid cells and accumulate at the filiform apparatus, where arriving pollen tubes communicate with the embryo sac. EN14 strongly and specifically interacts with the extracellular domain of the receptor-like kinase FERONIA, localized at the synergid cell surface and known to critically control pollen tube reception [6]. Wild-type pollen tubes failed to arrest growth and to rupture after entering the ovules of quintuple loss-of-function EN mutants, indicating a central role of ENs in male-female communication and pollen tube reception. Moreover, overexpression of EN15 by the endogenous promoter caused disturbed pollen tube guidance and reduced fertility. These data suggest that female-derived GPI-anchored ENODLs play an essential role in male-female communication and fertilization.
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Affiliation(s)
- Yingnan Hou
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at School of Life Sciences, Peking University, Beijing 100871, PRC
| | - Xinyang Guo
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at School of Life Sciences, Peking University, Beijing 100871, PRC
| | - Philipp Cyprys
- Department of Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany
| | - Ying Zhang
- Waksman Institute of Microbiology, Rutgers, State University of New Jersey, Piscataway, NJ 08854, USA
| | - Andrea Bleckmann
- Department of Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany
| | - Le Cai
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at School of Life Sciences, Peking University, Beijing 100871, PRC
| | - Qingpei Huang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at School of Life Sciences, Peking University, Beijing 100871, PRC
| | - Yu Luo
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at School of Life Sciences, Peking University, Beijing 100871, PRC
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at School of Life Sciences, Peking University, Beijing 100871, PRC; National Plant Gene Research Center (Beijing), Beijing 100101, PRC
| | - Thomas Dresselhaus
- Department of Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers, State University of New Jersey, Piscataway, NJ 08854, USA
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at School of Life Sciences, Peking University, Beijing 100871, PRC; National Plant Gene Research Center (Beijing), Beijing 100101, PRC.
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14
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Krauchunas AR, Marcello MR, Singson A. The molecular complexity of fertilization: Introducing the concept of a fertilization synapse. Mol Reprod Dev 2016; 83:376-86. [PMID: 26970099 DOI: 10.1002/mrd.22634] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/22/2016] [Indexed: 01/27/2023]
Abstract
The details of sperm-egg interactions remain a relative mystery despite many decades of research. As new molecular complexities are being discovered, we need to revise the framework in which we think about fertilization. As such, we propose that fertilization involves the formation of a synapse between the sperm and egg. A cellular synapse is a structure that mediates cell adhesion, signaling, and secretion through specialized zones of interaction and polarity. In this review, we draw parallels between the immune synapse and fertilization, and argue that we should consider sperm-egg recognition, binding, and fusion in the context of a "fertilization synapse." Mol. Reprod. Dev. 83: 376-386, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Amber R Krauchunas
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey
| | | | - Andrew Singson
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey
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15
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Dai X, Zhang M, Lu Y, Miao Y, Zhou C, Sun S, Xiong B. Melamine Impairs Female Fertility via Suppressing Protein Level of Juno in Mouse Eggs. PLoS One 2015; 10:e0144248. [PMID: 26633308 PMCID: PMC4669189 DOI: 10.1371/journal.pone.0144248] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 11/15/2015] [Indexed: 11/19/2022] Open
Abstract
Melamine is an organic nitrogenous compound widely used as an industrial chemical, and it has been recently reported by us that melamine has a toxic effect on the female reproductive system in mice, and renders females subfertile; the molecular basis, however, has not been adequately assessed. In the present study, we explore the underlying mechanism regarding how melamine compromises fertility in the mouse. The data showed that melamine exposure significantly impaired the fertilization capability of the egg during in vitro fertilization. To further figure out the cause, we analyzed ovastacin localization and protein level, the sperm binding ability of zona pellucida, and ZP2 cleavage status in unfertilized eggs from melamine fed mice, and no obvious differences were found between control and treatment groups. However, the protein level of Juno on the egg plasma membrane in the high-dose feeding group indeed significantly decreased compared to the control group. Thus, these data suggest that melamine compromises female fertility via suppressing Juno protein level on the egg membrane.
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Affiliation(s)
- Xiaoxin Dai
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 20095, China
| | - Mianqun Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 20095, China
| | - Yajuan Lu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 20095, China
| | - Yilong Miao
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 20095, China
| | - Changyin Zhou
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 20095, China
| | - Shaochen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 20095, China
| | - Bo Xiong
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 20095, China
- * E-mail:
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16
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Fujihara Y, Ikawa M. GPI-AP release in cellular, developmental, and reproductive biology. J Lipid Res 2015; 57:538-45. [PMID: 26593072 DOI: 10.1194/jlr.r063032] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Indexed: 12/13/2022] Open
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) contain a covalently linked GPI anchor located on outer cell membranes. GPI-APs are ubiquitously conserved from protozoa to vertebrates and are critical for physiological events such as development, immunity, and neurogenesis in vertebrates. Both membrane-anchored and soluble GPI-APs play a role in regulating their protein conformation and functional properties. Several pathways mediate the release of GPI-APs from the plasma membrane by vesiculation or cleavage. Phospholipases and putative substrate-specific GPI-AP-releasing enzymes, such as NOTUM, glycerophosphodiesterase 2, and angiotensin-converting enzyme, have been characterized in mammals. Here, the protein modifications resulting from the cleavage of the GPI anchor are discussed in the context of its physiological functions.
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Affiliation(s)
- Yoshitaka Fujihara
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
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17
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Kinoshita T, Fujita M. Biosynthesis of GPI-anchored proteins: special emphasis on GPI lipid remodeling. J Lipid Res 2015; 57:6-24. [PMID: 26563290 DOI: 10.1194/jlr.r063313] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Indexed: 02/06/2023] Open
Abstract
Glycosylphosphatidylinositols (GPIs) act as membrane anchors of many eukaryotic cell surface proteins. GPIs in various organisms have a common backbone consisting of ethanolamine phosphate (EtNP), three mannoses (Mans), one non-N-acetylated glucosamine, and inositol phospholipid, whose structure is EtNP-6Manα-2Manα-6Manα-4GlNα-6myoinositol-P-lipid. The lipid part is either phosphatidylinositol of diacyl or 1-alkyl-2-acyl form, or inositol phosphoceramide. GPIs are attached to proteins via an amide bond between the C-terminal carboxyl group and an amino group of EtNP. Fatty chains of inositol phospholipids are inserted into the outer leaflet of the plasma membrane. More than 150 different human proteins are GPI anchored, whose functions include enzymes, adhesion molecules, receptors, protease inhibitors, transcytotic transporters, and complement regulators. GPI modification imparts proteins with unique characteristics, such as association with membrane microdomains or rafts, transient homodimerization, release from the membrane by cleavage in the GPI moiety, and apical sorting in polarized cells. GPI anchoring is essential for mammalian embryogenesis, development, neurogenesis, fertilization, and immune system. Mutations in genes involved in remodeling of the GPI lipid moiety cause human diseases characterized by neurological abnormalities. Yeast Saccharomyces cerevisiae has >60 GPI-anchored proteins (GPI-APs). GPI is essential for growth of yeast. In this review, we discuss biosynthesis of GPI-APs in mammalian cells and yeast with emphasis on the lipid moiety.
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Affiliation(s)
- Taroh Kinoshita
- WPI Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
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18
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Wright GJ, Bianchi E. The challenges involved in elucidating the molecular basis of sperm-egg recognition in mammals and approaches to overcome them. Cell Tissue Res 2015. [PMID: 26224538 PMCID: PMC4700105 DOI: 10.1007/s00441-015-2243-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sexual reproduction is used by many different organisms to create a new generation of genetically distinct progeny. Cells originating from separate sexes or mating types segregate their genetic material into haploid gametes which must then recognize and fuse with each other in a process known as fertilization to form a diploid zygote. Despite the central importance of fertilization, we know remarkably little about the molecular mechanisms that are involved in how gametes recognize each other, particularly in mammals, although the proteins that are displayed on their surfaces are almost certainly involved. This paucity of knowledge is largely due to both the unique biological properties of mammalian gametes (sperm and egg) which make them experimentally difficult to manipulate, and the technical challenges of identifying interactions between membrane-embedded cell surface receptor proteins. In this review, we will discuss our current knowledge of animal gamete recognition, highlighting where important contributions to our understanding were made, why particular model systems were helpful, and why progress in mammals has been particularly challenging. We discuss how the development of mammalian in vitro fertilization and targeted gene disruption in mice were important technological advances that triggered progress. We argue that approaches employed to discover novel interactions between cell surface gamete recognition proteins should account for the unusual biochemical properties of membrane proteins and the typically highly transient nature of their interactions. Finally, we describe how these principles were applied to identify Juno as the egg receptor for sperm Izumo1, an interaction that is essential for mammalian fertilization.
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Affiliation(s)
- Gavin J Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Enrica Bianchi
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.
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19
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Benkhalifa M, Madkour A, Louanjli N, Bouamoud N, Saadani B, Kaarouch I, Chahine H, Sefrioui O, Merviel P, Copin H. From global proteome profiling to single targeted molecules of follicular fluid and oocyte: contribution to embryo development and IVF outcome. Expert Rev Proteomics 2015; 12:407-23. [DOI: 10.1586/14789450.2015.1056782] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Otsuka-Kanazawa S, Ichii O, Kon Y. Testicular oocytes in MRL/MpJ mice possess similar morphological, genetic, and functional characteristics to ovarian oocytes. Mech Dev 2015; 137:23-32. [PMID: 25892298 DOI: 10.1016/j.mod.2015.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 04/03/2015] [Accepted: 04/09/2015] [Indexed: 11/26/2022]
Abstract
In general, mammalian males produce only spermatozoa in their testes and females produce only oocytes in their ovaries. However, newborn MRL/MpJ male mice produce oocytes within their testes. In this study, we examined the initiation and progression of oogenesis in fetal and neonatal MRL/MpJ mouse testes and evaluated the characteristics of testicular oocytes. Germ cells with positive reactions to oogenesis markers such as NOBOX oogenesis homeobox and synaptonemal complex protein 3 were observed in the MRL/MpJ fetal testes on embryonic day 18.5. These fetal testicular oocytes possessed maternal-specific methylation patterns of histone and DNA. The level of DNA methylation was still low in postnatal testicular oocytes at day 14 after birth. Additionally, the postnatal testicular oocytes contained both X and Y chromosomes and had the ability to fuse with sperm. These results suggest that some XY germ cells in fetal testes of MRL/MpJ mice enter meiosis prematurely, undergo oogenesis, and differentiate into oocytes. In addition, MRL/MpJ testicular oocytes have the ability to carry on oogenesis before and shortly after birth until they obtain some of the morphological, epigenetic, and functional characteristics of oocytes.
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Affiliation(s)
- Saori Otsuka-Kanazawa
- Laboratory of Anatomy, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
| | - Osamu Ichii
- Laboratory of Anatomy, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yasuhiro Kon
- Laboratory of Anatomy, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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21
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Molecular and cellular mechanisms of sperm-oocyte interactions opinions relative to in vitro fertilization (IVF). Int J Mol Sci 2014; 15:12972-97. [PMID: 25054321 PMCID: PMC4139886 DOI: 10.3390/ijms150712972] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/07/2014] [Accepted: 06/24/2014] [Indexed: 12/17/2022] Open
Abstract
One of the biggest prerequisites for pregnancy is the fertilization step, where a human haploid spermatozoon interacts and penetrates one haploid oocyte in order to produce the diploid zygote. Although fertilization is defined by the presence of two pronuclei and the extraction of the second polar body the process itself requires preparation of both gametes for fertilization to take place at a specific time. These preparations include a number of consecutive biochemical and molecular events with the help of specific molecules and with the consequential interaction between the two gametes. These events take place at three different levels and in a precise order, where the moving spermatozoon penetrates (a) the outer vestments of the oocyte, known as the cumulus cell layer; (b) the zona pellucida (ZP); where exocytosis of the acrosome contents take place and (c) direct interaction of the spermatozoon with the plasma membrane of the oocyte, which involves a firm adhesion of the head of the spermatozoon with the oocyte plasma membrane that culminates with the fusion of both sperm and oocyte membranes (Part I). After the above interactions, a cascade of molecular signal transductions is initiated which results in oocyte activation. Soon after the entry of the first spermatozoon into the oocyte and oocyte activation, the oocyte’s coat (the ZP) and the oocyte’s plasma membrane seem to change quickly in order to initiate a fast block to a second spermatozoon (Part II). Sometimes, two spermatozoa fuse with one oocyte, an incidence of 1%–2%, resulting in polyploid fetuses that account for up to 10%–20% of spontaneously aborted human conceptuses. The present review aims to focus on the first part of the human sperm and oocyte interactions, emphasizing the latest molecular and cellular mechanisms controlling this process.
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22
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Klinovska K, Sebkova N, Dvorakova-Hortova K. Sperm-egg fusion: a molecular enigma of mammalian reproduction. Int J Mol Sci 2014; 15:10652-68. [PMID: 24933635 PMCID: PMC4100174 DOI: 10.3390/ijms150610652] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/13/2014] [Accepted: 05/30/2014] [Indexed: 12/14/2022] Open
Abstract
The mechanism of gamete fusion remains largely unknown on a molecular level despite its indisputable significance. Only a few of the molecules required for membrane interaction are known, among them IZUMO1, which is present on sperm, tetraspanin CD9, which is present on the egg, and the newly found oolema protein named Juno. A concept of a large multiprotein complex on both membranes forming fusion machinery has recently emerged. The Juno and IZUMO1, up to present, is the only known extracellular receptor pair in the process of fertilization, thus, facilitating the essential binding of gametes. However, neither IZUMO1 nor Juno appears to be the fusogenic protein. At the same time, the tetraspanin is expected to play a role in organizing the egg membrane order and to interact laterally with other factors. This review summarizes, to present, the known molecules involved in the process of sperm-egg fusion. The complexity and expected redundancy of the involved factors makes the process an intricate and still poorly understood mechanism, which is difficult to comprehend in its full distinction.
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Affiliation(s)
- Karolina Klinovska
- BIOCEV Group, Department of Zoology, Charles University in Prague, Vinicna 7, Prague 2 128 44, Czech Republic.
| | - Natasa Sebkova
- BIOCEV Group, Department of Zoology, Charles University in Prague, Vinicna 7, Prague 2 128 44, Czech Republic.
| | - Katerina Dvorakova-Hortova
- BIOCEV Group, Department of Zoology, Charles University in Prague, Vinicna 7, Prague 2 128 44, Czech Republic.
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23
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Bianchi E, Doe B, Goulding D, Wright GJ. Juno is the egg Izumo receptor and is essential for mammalian fertilization. Nature 2014; 508:483-7. [PMID: 24739963 PMCID: PMC3998876 DOI: 10.1038/nature13203] [Citation(s) in RCA: 385] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/05/2014] [Indexed: 12/21/2022]
Abstract
Fertilization occurs when sperm and egg recognize each other and fuse to form a new, genetically distinct organism. The molecular basis of sperm-egg recognition is unknown, but is likely to require interactions between receptor proteins displayed on their surface. Izumo1 is an essential sperm cell-surface protein, but its receptor on the egg has not been described. Here we identify folate receptor 4 (Folr4) as the receptor for Izumo1 on the mouse egg, and propose to rename it Juno. We show that the Izumo1-Juno interaction is conserved within several mammalian species, including humans. Female mice lacking Juno are infertile and Juno-deficient eggs do not fuse with normal sperm. Rapid shedding of Juno from the oolemma after fertilization suggests a mechanism for the membrane block to polyspermy, ensuring eggs normally fuse with just a single sperm. Our discovery of an essential receptor pair at the nexus of conception provides opportunities for the rational development of new fertility treatments and contraceptives.
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Affiliation(s)
- Enrica Bianchi
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Brendan Doe
- Mouse Production Team, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - David Goulding
- Electron and Advanced Light Microscopy Suite, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Gavin J Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
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24
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Pires ES, Hlavin C, Macnamara E, Ishola-Gbenla K, Doerwaldt C, Chamberlain C, Klotz K, Herr AK, Khole A, Chertihin O, Curnow E, Feldman SH, Mandal A, Shetty J, Flickinger C, Herr JC. SAS1B protein [ovastacin] shows temporal and spatial restriction to oocytes in several eutherian orders and initiates translation at the primary to secondary follicle transition. Dev Dyn 2013; 242:1405-26. [PMID: 24038607 DOI: 10.1002/dvdy.24040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/07/2013] [Accepted: 08/16/2013] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Sperm Acrosomal SLLP1 Binding (SAS1B) protein (ovastacin) is an oolemmal binding partner for the intra-acrosomal sperm protein SLLP1. RESULTS Immunohistochemical localization revealed that SAS1B translation is restricted among adult tissues to the ovary and oocytes, SAS1B appearing first in follicles at the primary-secondary transition. Quiescent oocytes within primordial follicles and primary follicles did not stain for SAS1B. Examination of neonatal rat ovaries revealed SAS1B expression first as faint signals in postnatal day 3 oocytes, with SAS1B protein staining intensifying with oocyte growth. Irrespective of animal age or estrus stage, SAS1B was seen only in oocytes of follicles that initiated a second granulosa cell layer. The precise temporal and spatial onset of SAS1B expression was conserved in adult ovaries in seven eutherian species, including nonhuman primates. Immunoelectron micrographs localized SAS1B within cortical granules in MII oocytes. A population of SAS1B localized on the oolemma predominantly in the microvillar region anti-podal to the nucleus in ovulated MII rat oocytes and on the oolemma in macaque GV oocytes. CONCLUSIONS The restricted expression of SAS1B protein in growing oocytes, absence in the ovarian reserve, and localization on the oolemma suggest this zinc metalloprotease deserves consideration as a candidate target for reversible female contraceptive strategies.
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Affiliation(s)
- Eusebio S Pires
- Department of Cell Biology, Center for Research in Contraceptive and Reproductive Health, University of Virginia, Charlottesville, Virginia
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25
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Li S, Ge FR, Xu M, Zhao XY, Huang GQ, Zhou LZ, Wang JG, Kombrink A, McCormick S, Zhang XS, Zhang Y. Arabidopsis COBRA-LIKE 10, a GPI-anchored protein, mediates directional growth of pollen tubes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 74:486-97. [PMID: 23384085 DOI: 10.1111/tpj.12139] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 01/29/2013] [Accepted: 01/31/2012] [Indexed: 05/06/2023]
Abstract
Successful reproduction of flowering plants requires constant communication between female tissues and growing pollen tubes. Female cells secrete molecules and peptides as nutrients or guidance cues for fast and directional tube growth, which is executed by dynamic changes of intracellular activities within pollen tubes. Compared with the extensive interest in female cues and intracellular activities of pollen tubes, how female cues are sensed and interpreted intracellularly in pollen is poorly understood. We show here that COBL10, a glycosylphosphatidylinositol (GPI)-anchored protein, is one component of this pollen tube internal machinery. Mutations in COBL10 caused gametophytic male sterility due to reduced pollen tube growth and compromised directional sensing in the female transmitting tract. Deposition of the apical pectin cap and cellulose microfibrils was disrupted in cobl10 pollen tubes. Pollen tube localization of COBL10 at the apical plasma membrane is critical for its function and relies on proper GPI processing and its C-terminal hydrophobic residues. GPI-anchored proteins are widespread cell sensors in mammals, especially during egg-sperm communication. Our results that COBL10 is critical for directional growth of pollen tubes suggest that they play critical roles in cell-cell communications in plants.
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Affiliation(s)
- Sha Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018 Shandong, China
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Buschiazzo J, Ialy-Radio C, Auer J, Wolf JP, Serres C, Lefèvre B, Ziyyat A. Cholesterol depletion disorganizes oocyte membrane rafts altering mouse fertilization. PLoS One 2013; 8:e62919. [PMID: 23638166 PMCID: PMC3636221 DOI: 10.1371/journal.pone.0062919] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 03/29/2013] [Indexed: 11/18/2022] Open
Abstract
Drastic membrane reorganization occurs when mammalian sperm binds to and fuses with the oocyte membrane. Two oocyte protein families are essential for fertilization, tetraspanins and glycosylphosphatidylinositol-anchored proteins. The firsts are associated to tetraspanin-enriched microdomains and the seconds to lipid rafts. Here we report membrane raft involvement in mouse fertilization assessed by cholesterol modulation using methyl-β-cyclodextrin. Cholesterol removal induced: (1) a decrease of the fertilization rate and index; and (2) a delay in the extrusion of the second polar body. Cholesterol repletion recovered the fertilization ability of cholesterol-depleted oocytes, indicating reversibility of these effects. In vivo time-lapse analyses using fluorescent cholesterol permitted to identify the time-point at which the probe is mainly located at the plasma membrane enabling the estimation of the extent of the cholesterol depletion. We confirmed that the mouse oocyte is rich in rafts according to the presence of the raft marker lipid, ganglioside GM1 on the membrane of living oocytes and we identified the coexistence of two types of microdomains, planar rafts and caveolae-like structures, by terms of two differential rafts markers, flotillin-2 and caveolin-1, respectively. Moreover, this is the first report that shows characteristic caveolae-like invaginations in the mouse oocyte identified by electron microscopy. Raft disruption by cholesterol depletion disturbed the subcellular localization of the signal molecule c-Src and the inhibition of Src kinase proteins prevented second polar body extrusion, consistent with a role of Src-related kinases in fertilization via signaling complexes. Our data highlight the functional importance of intact membrane rafts for mouse fertilization and its dependence on cholesterol.
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Affiliation(s)
- Jorgelina Buschiazzo
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, F75014 Paris, France
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (UNS-CONICET), Bahía Blanca, Argentina
| | - Come Ialy-Radio
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, F75014 Paris, France
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques. F75014 Paris, France
| | - Jana Auer
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, F75014 Paris, France
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques. F75014 Paris, France
| | - Jean-Philippe Wolf
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, F75014 Paris, France
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques. F75014 Paris, France
- Service d’Histologie Embryologie Biologie de la Reproduction Hôpital Cochin, AP-HP, F75014 Paris, France
| | - Catherine Serres
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, F75014 Paris, France
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques. F75014 Paris, France
| | - Brigitte Lefèvre
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, F75014 Paris, France
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques. F75014 Paris, France
| | - Ahmed Ziyyat
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, F75014 Paris, France
- INSERM U1016, Institut Cochin, Université Paris Descartes, 24 rue du Faubourg Saint-Jacques. F75014 Paris, France
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Hu MW, Wang ZB, Schatten H, Sun QY. New understandings on folliculogenesis/oogenesis regulation in mouse as revealed by conditional knockout. J Genet Genomics 2012; 39:61-8. [PMID: 22361505 DOI: 10.1016/j.jgg.2012.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 12/28/2011] [Accepted: 01/05/2012] [Indexed: 01/27/2023]
Abstract
In comparison to conventional knockout technology and in vitro research methods, conditional gene knockout has remarkable advantages. In the past decade, especially during the past five years, conditional knockout approaches have been used to study the regulation of folliculogenesis, follicle growth, oocyte maturation and other major reproductive events. In this review, we summarize the recent findings about folliculogenesis/oogenesis regulation, including the functions of four signaling cascades or glycoprotein domains that have been extensively studied by conditional gene deletion. Several other still fragmented areas of related work are introduced which are awaiting clarification. We have also discussed the future potential of this technology in clarifying gene functions in reproductive biology.
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Affiliation(s)
- Meng-Wen Hu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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Sachdev M, Mandal A, Mulders S, Digilio LC, Panneerdoss S, Suryavathi V, Pires E, Klotz KL, Hermens L, Herrero MB, Flickinger CJ, van Duin M, Herr JC. Oocyte specific oolemmal SAS1B involved in sperm binding through intra-acrosomal SLLP1 during fertilization. Dev Biol 2011; 363:40-51. [PMID: 22206759 DOI: 10.1016/j.ydbio.2011.12.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 12/08/2011] [Accepted: 12/12/2011] [Indexed: 10/14/2022]
Abstract
Molecular mechanisms by which fertilization competent acrosome-reacted sperm bind to the oolemma remain uncharacterized. To identify oolemmal binding partner(s) for sperm acrosomal ligands, affinity panning was performed with mouse oocyte lysates using sperm acrosomal protein, SLLP1 as a target. An oocyte specific membrane metalloproteinase, SAS1B (Sperm Acrosomal SLLP1 Binding), was identified as a SLLP1 binding partner. cDNA cloning revealed six SAS1B splice variants, each containing a zinc binding active site and a putative transmembrane domain, with signal peptides in three variants. SAS1B transcripts were ovary specific. SAS1B protein was first detected in early secondary follicles in day 3 ovaries. Immunofluorescence localized SAS1B to the microvillar oolemma of M2 oocytes. After fertilization, SAS1B decreased on the oolemma and became virtually undetectable in blastocysts. In transfected CHO-K1 cells SAS1B localized to the surface of unpermeabilized cells. Recombinant and native SLLP1 co-localized with SAS1B to the microvillar domain of ovulated M2 oocytes. Molecular interactions between mouse SLLP1 and SAS1B were demonstrated by surface plasmon resonance, far-western, yeast two-hybrid, recombinant- and native-co-IP analyses. SAS1B bound to SLLP1 with high affinity. SAS1B had protease activity, and SAS1B protein or antibody significantly inhibited fertilization. SAS1B knockout female mice showed a 34% reduction in fertility. The study identified SAS1B-SLLP1 as a pair of novel sperm-egg binding partners involving the oolemma and intra-acrosomal compartment during fertilization.
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Affiliation(s)
- Monika Sachdev
- Department of Cell Biology, Center for Research in Contraceptive and Reproductive Health, University of Virginia, Charlottesville, VA 22908, USA
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29
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Abstract
A crucial step of fertilization is the sperm-egg interaction that allows the two gametes to fuse and create the zygote. In the mouse, CD9 on the egg and IZUMO1 on the sperm stand out as critical players, as Cd9(-/-) and Izumo1(-/-) mice are healthy but infertile or severely subfertile due to defective sperm-egg interaction. Moreover, work on several nonmammalian organisms has identified some of the most intriguing candidates implicated in sperm-egg interaction. Understanding of gamete membrane interactions is advancing through characterization of in vivo and in vitro fertilization phenotypes, including insights from less robust phenotypes that highlight potential supporting (albeit not absolutely essential) players. An emerging theme is that there are varied roles for gamete molecules that participate in sperm-egg interactions. Such roles include not only functioning as fusogens, or as adhesion molecules for the opposite gamete, but also functioning through interactions in cis with other proteins to regulate membrane order and functionality.
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Affiliation(s)
- Janice P Evans
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.
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30
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Molecular and cellular mechanisms of mammalian cell fusion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 713:33-64. [PMID: 21432013 DOI: 10.1007/978-94-007-0763-4_4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The fusion of one cell with another occurs in development, injury and disease. Despite the diversity of fusion events, five steps in sequence appear common. These steps include programming fusion-competent status, chemotaxis, membrane adhesion, membrane fusion, and post-fusion resetting. Recent advances in the field start to reveal the molecules involved in each step. This review focuses on some key molecules and cellular events of cell fusion in mammals. Increasing evidence demonstrates that membrane lipid rafts, adhesion proteins and actin rearrangement are critical in the final step of membrane fusion. Here we propose a new model for the formation and expansion of membrane fusion pores based on recent observations on myotube formation. In this model, membrane lipid rafts first recruit adhesion molecules and align with opposing membranes, with the help of a cortical actin "wall" as a rigid supportive platform. Second, the membrane adhesion proteins interact with each other and trigger actin rearrangement, which leads to rapid dispersion of lipid rafts and flow of a highly fluidic phospholipid bilayer into the site. Finally, the opposing phospholipid bilayers are then pushed into direct contact leading to the formation of fusion pores by the force generated through actin polymerization. The actin polymerization generated force also drives the expansion of the fusion pores. However, several key questions about the process of cell fusion still remain to be explored. The understanding of the mechanisms of cell fusion may provide new opportunities in correcting development disorders or regenerating damaged tissues by inhibiting or promoting molecular events associated with fusion.
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31
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CD9 tetraspanin generates fusion competent sites on the egg membrane for mammalian fertilization. Proc Natl Acad Sci U S A 2011; 108:10946-51. [PMID: 21690351 DOI: 10.1073/pnas.1017400108] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
CD9 tetraspanin is the only egg membrane protein known to be essential for fertilization. To investigate its role, we have measured, on a unique acrosome reacted sperm brought in contact with an egg, the adhesion probability and strength with a sensitivity of a single molecule attachment. Probing the binding events at different locations of wild-type egg we described different modes of interaction. Here, we show that more gamete adhesion events occur on Cd9 null eggs but that the strongest interaction mode disappears. We propose that sperm-egg fusion is a direct consequence of CD9 controlled sperm-egg adhesion properties. CD9 generates adhesion sites responsible for the strongest of the observed gamete interaction. These strong adhesion sites impose, during the whole interaction lifetime, a tight proximity of the gamete membranes, which is a requirement for fusion to take place. The CD9-induced adhesion sites would be the actual location where fusion occurs.
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32
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Gadella BM, Evans JP. Membrane Fusions During Mammalian Fertilization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 713:65-80. [DOI: 10.1007/978-94-007-0763-4_5] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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33
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New Insights into the Mechanisms and Roles of Cell–Cell Fusion. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 289:149-209. [DOI: 10.1016/b978-0-12-386039-2.00005-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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34
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Inoue N, Ikawa M, Okabe M. The mechanism of sperm-egg interaction and the involvement of IZUMO1 in fusion. Asian J Androl 2010; 13:81-7. [PMID: 21057513 DOI: 10.1038/aja.2010.70] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
An average human ejaculate contains over 100 million sperm, but only a few succeed in accomplishing the journey to an egg by migration through the female reproductive tract. Among these few sperm, only one participates in fertilization. There might be an ingenious molecular mechanism to ensure that the very best sperm fertilize an egg. However, recent gene disruption experiments in mice have revealed that many factors previously described as important for fertilization are largely dispensable. One could argue that the fertilization mechanism is made robust against gene disruptions. However, this is not likely, as there are already six different gene-disrupted mouse lines (Calmegin, Adam1a, Adam2, Adam3, Ace and Pgap1), all of which result in male sterility. The sperm from these animals are known to have defective zona-binding ability and at the same time lose oviduct-migrating ability. Concerning sperm-zona binding, the widely accepted involvement of sugar moiety on zona pellucida 3 (ZP3) is indicated to be dispensable by gene disruption experiments. Thus, the landscape of the mechanism of fertilization is revolving considerably. In the sperm-egg fusion process, CD9 on egg and IZUMO1 on sperm have emerged as essential factors. This review focuses on the mechanism of fertilization elucidated by gene-manipulated animals.
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Affiliation(s)
- Naokazu Inoue
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
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35
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Hugon-Rodin J, Chabbert-Buffet N, Bouchard P. The future of women's contraception: stakes and modalities. Ann N Y Acad Sci 2010; 1205:230-9. [DOI: 10.1111/j.1749-6632.2010.05688.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Yurttas P, Morency E, Coonrod SA. Use of proteomics to identify highly abundant maternal factors that drive the egg-to-embryo transition. Reproduction 2010; 139:809-23. [DOI: 10.1530/rep-09-0538] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
As IVF becomes an increasingly popular method for human reproduction, it is more critical than ever to understand the unique molecular composition of the mammalian oocyte. DNA microarray studies have successfully provided valuable information regarding the identity and dynamics of factors at the transcriptional level. However, the oocyte transcribes and stores a large amount of material that plays no obvious role in oogenesis, but instead is required to regulate embryogenesis. Therefore, an accurate picture of the functional state of the oocyte requires both transcriptional profiling and proteomics. Here, we summarize our previous studies of the oocyte proteome, and present new panels of oocyte proteins that we recently identified in screens of metaphase II-arrested mouse oocytes. Importantly, our studies indicate that several abundant oocyte proteins are not, as one might predict, ubiquitous housekeeping proteins, but instead are unique to the oocyte. Furthermore, mouse studies indicate that a number of these factors arise from maternal effect genes (MEGs). One of the identified MEG proteins, peptidylarginine deiminase 6, localizes to and is required for the formation of a poorly characterized, highly abundant cytoplasmic structure: the oocyte cytoplasmic lattices. Additionally, a number of other MEG-derived abundant proteins identified in our proteomic screens have been found by others to localize to another unique oocyte feature: the subcortical maternal complex. Based on these observations, we put forth the hypothesis that the mammalian oocyte contains several unique storage structures, which we have named maternal effect structures, that facilitate the oocyte-to-embryo transition.
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37
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Ikawa M, Inoue N, Benham AM, Okabe M. Fertilization: a sperm's journey to and interaction with the oocyte. J Clin Invest 2010; 120:984-94. [PMID: 20364096 DOI: 10.1172/jci41585] [Citation(s) in RCA: 201] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mammalian fertilization comprises sperm migration through the female reproductive tract, biochemical and morphological changes to sperm, and sperm-egg interaction in the oviduct. Recent gene knockout approaches in mice have revealed that many factors previously considered important for fertilization are largely dispensable, or if they are essential, they have an unexpected function. These results indicate that what has been observed in in vitro fertilization (IVF) differs significantly from what occurs during "physiological" fertilization. This Review focuses on the advantages of studying fertilization using gene-manipulated animals and highlights an emerging molecular mechanism of mammalian fertilization.
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Affiliation(s)
- Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Yamadaoka 3-1, Suita, Osaka, 565-0871, Japan
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38
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Abstract
PROBLEM The role of progesterone-dependent immunomodulation in the maintenance of normal pregnancy. METHODS In vitro and in vivo data on the effect that progesterone and its mediator progesterone-induced blocking factor (PIBF) exert on the immune functions of pregnant women are reviewed, together with clinical findings. RESULTS Activated pregnancy lymphocytes express progesterone receptors, which enable progesterone to induce a protein called PIBF. PIBF increases Th2 type cytokine production by signaling via a novel type of IL-4 receptor and activating the Jak/STAT pathway. PIBF inhibits phosholipase A2, thus reduces prostaglandin synthesis. PIBF inhibits perforin release in human decidual lymphocytes and reduces the deleterious effect of high NK activity on murine pregnancy. PIBF production is a characteristic feature of normal human pregnancy, and its concentration is reduced in threatened pregnancies. PIBF mRNA and protein are expressed in a variety of malignant tumors. Inhibition of PIBF synthesis increases survival rates of leukemic mice. CONCLUSION Progesterone-induced blocking factor is produced by pregnancy lymphocytes and also by malignant tumors. The PIBF-induced Th2-dominant immune response is favorable during pregnancy but might facilitate tumor growth by suppressing local antitumor immune responses.
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Affiliation(s)
- Julia Szekeres-Bartho
- Department of Medical Microbiology and Immunology, Medical School, Pecs University, H-7643 Pecs, Hungary.
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39
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Lefèvre B, Wolf JP, Ziyyat A. Sperm-egg interaction: is there a link between tetraspanin(s) and GPI-anchored protein(s)? Bioessays 2010; 32:143-52. [DOI: 10.1002/bies.200900159] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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40
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Abstract
Infertility adversely affects many couples worldwide. Conversely, the exponential increase in world population threatens our planet and its resources. Therefore, a greater understanding of the fundamental cellular and molecular events that control the size of the primordial follicle pool and follicular development is of utmost importance to develop improved in vitro fertilization as well as to design novel approaches to regulate fertility. In this review we attempt to highlight some new advances in basic research of the mammalian ovary that have occurred in recent years focusing primarily on mouse models that have contributed to our understanding of ovarian follicle formation, development, and ovulation. We hope that these new insights into ovarian function will trigger more research and translation to clinically relevant problems.
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41
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Glazar AI, Evans JP. Immunoglobulin superfamily member IgSF8 (EWI-2) and CD9 in fertilisation: evidence of distinct functions for CD9 and a CD9-associated protein in mammalian sperm-egg interaction. Reprod Fertil Dev 2009; 21:293-303. [PMID: 19210920 DOI: 10.1071/rd08158] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 09/29/2008] [Indexed: 11/23/2022] Open
Abstract
On the mouse egg, the tetraspanin CD9 is nearly essential for sperm-egg fusion, with another tetraspanin, CD81, playing a complementary role. Based on what is known about these proteins, egg tetraspanins are likely to be involved in regulation of membrane order through associations with other egg membrane proteins. Here, we identify a first-level interaction (stable in 1% Triton X-100) between CD9 and the immunoglobulin superfamily member IgSF8 (also known as EWI-2), the first evidence in eggs of such an interaction of CD9 with another protein. We also compared the effects of antibody-mediated perturbation of IgSF8 and CD9, evaluating the robustness of these perturbations in IVF conditions that heavily favour fertilisation and those in which fertilisation occurs less frequently. These studies demonstrate that IgSF8 participates in mouse gamete interactions and identify discrete effects of antibody-mediated perturbation of CD9 and IgSF8. An anti-IgSF8 antibody had moderate inhibitory effects on sperm-egg binding, whereas an anti-CD9 antibody significantly inhibited sperm-egg fusion and, in certain assays, had an inhibitory effect on binding as well. The present study highlights the critical importance of design of IVF experiments for the detection of different effects of experimental manipulations on gamete interactions.
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Affiliation(s)
- Amanda I Glazar
- Department of Biochemistry, Division of Reproductive Biology, Bloomberg School of Public Health, Johns Hopkins University, 615 N. Wolf Street, Baltimore, MD 21205, USA
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42
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Coimbra S, Costa M, Jones B, Mendes MA, Pereira LG. Pollen grain development is compromised in Arabidopsis agp6 agp11 null mutants. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3133-42. [PMID: 19433479 PMCID: PMC2718217 DOI: 10.1093/jxb/erp148] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 03/30/2009] [Accepted: 04/09/2009] [Indexed: 05/18/2023]
Abstract
Arabinogalactan proteins (AGPs) are structurally complex plasma membrane and cell wall proteoglycans that are implicated in diverse developmental processes, including plant sexual reproduction. Male gametogenesis (pollen grain development) is fundamental to plant sexual reproduction. The role of two abundant, pollen-specific AGPs, AGP6, and AGP11, have been investigated here. The pollen specificity of these proteoglycans suggested that they are integral to pollen biogenesis and their strong sequence homology indicated a potential for overlapping function. Indeed, single gene transposon insertion knockouts for both AGPs showed no discernible phenotype. However, in plants homozygous for one of the insertions and heterozygous for the other, in homozygous double mutants, and in RNAi and amiRNA transgenic plants that were down-regulated for both genes, many pollen grains failed to develop normally, leading to their collapse. The microscopic observations of these aborted pollen grains showed a condensed cytoplasm, membrane blebbing and the presence of small lytic vacuoles. Later in development, the generative cells that arise from mitotic divisions were not seen to go into the second mitosis. Anther wall development, the establishment of the endothecium thickenings, the opening of the stomium, and the deposition of the pollen coat were all normal in the knockout and knockdown lines. Our data provide strong evidence that these two proteoglycans have overlapping and important functions in gametophytic pollen grain development.
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Affiliation(s)
- Sílvia Coimbra
- Departamento de Botânica, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre 4169-007 Porto, Portugal.
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He ZY, Gupta S, Myles D, Primakoff P. Loss of surface EWI-2 on CD9 null oocytes. Mol Reprod Dev 2008; 76:629-36. [DOI: 10.1002/mrd.20991] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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44
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Sun QY, Liu K, Kikuchi K. Oocyte-specific knockout: a novel in vivo approach for studying gene functions during folliculogenesis, oocyte maturation, fertilization, and embryogenesis. Biol Reprod 2008; 79:1014-20. [PMID: 18753607 DOI: 10.1095/biolreprod.108.070409] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Knockout mice have been highly useful tools in helping to understand the functional roles of specific genes in development and diseases. However, in many cases, knockout mice are embryonic lethal, which prevents investigation into a number of important questions, or they display developmental abnormalities, including fertility defects. In contrast, conditional knockout, which is achieved by the Cre-LoxP system, can be used to delete a gene in a specific organ or tissue, or at a specific developmental stage. This technique has advantages over conventional knockout, especially when conventional knockout causes embryonic lethality or when the function of maternal transcripts in early development needs to be defined. Recently, a widely used practice has been used to specifically delete genes of interest in oocytes: Zp3-Cre or Gdf9-Cre transgenic mouse lines, in which Cre-recombinase expression is driven by oocyte-specific zona pellucida 3 (Zp3) promoter or growth differentiation factor 9 (Gdf9) promoter, are crossed with mice bearing floxed target genes. This novel in vivo approach has helped to increase the understanding of the functions of specific genes in folliculogenesis/oogenesis, oocyte maturation, fertilization, and embryogenesis. In this minireview we discuss recent advances in understanding the molecular mechanisms regulating major reproductive and developmental events as revealed by oocyte-specific conditional knockout and perspectives on this technology and related studies.
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Affiliation(s)
- Qing-Yuan Sun
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
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Swain JE, Pool TB. ART failure: oocyte contributions to unsuccessful fertilization. Hum Reprod Update 2008; 14:431-46. [DOI: 10.1093/humupd/dmn025] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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Williams SA, Stanley P. Mouse fertility is enhanced by oocyte-specific loss of core 1-derived O-glycans. FASEB J 2008; 22:2273-84. [PMID: 18276833 DOI: 10.1096/fj.07-101709] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Regulation of the number of eggs ovulated by different mammalian species remains poorly understood. Here we show that oocyte-specific deletion at the primary follicle stage of core 1 beta1,3-galactosyltransferase (T-synthase; generates core 1-derived O-glycans), leads to a sustained increase in fertility. T-syn mutant females ovulated 30-50% more eggs and had a sustained increase in litter size compared to controls. Ovarian weights and follicle numbers were greater in mutants, but follicular apoptosis was not decreased. The number of follicles entering the growing pool was unaltered, but 3-wk mutants ovulated fewer eggs, suggesting that increased fertility results from prolonged follicle development. T-syn mutant ovaries also contained numerous multiple-oocyte follicles (MOFs) that appeared to form by adjacent, predominantly preantral, follicles joining--a new mechanism for MOF generation. Ovulation of multiple eggs from MOFs was not the reason for increased fertility based on ovulated egg and corpora lutea numbers. Thus, the absence of T-synthase caused modified follicular development, leading to the maturation and ovulation of more follicles, to MOF formation at late stages of folliculogenesis, and to increased fertility. These results identify novel roles for glycoproteins from the oocyte as suppressors of fertility and regulators of follicular integrity in the mouse.
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Affiliation(s)
- Suzannah A Williams
- Department of Cell Biology, Albert Einstein College of Medicine, New York, New York 10461, USA
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Márton ML, Dresselhaus T. A comparison of early molecular fertilization mechanisms in animals and flowering plants. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s00497-007-0062-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Wassarman PM, Litscher ES. Mammalian fertilization is dependent on multiple membrane fusion events. Methods Mol Biol 2008; 475:99-113. [PMID: 18979240 DOI: 10.1007/978-1-59745-250-2_6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Successful completion of fertilization in mammals is dependent on three membrane fusion events. These are (1) the acrosome reaction of sperm, (2) the fusion of sperm and egg plasma membranes to form a zygote, and (3) the cortical reaction of fertilized eggs. Extensive research into the molecular basis of each of these events has identified candidate proteins and factors involved in fusion of membranes during the mammalian fertilization process. Some of this information is provided here.
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Affiliation(s)
- Paul M Wassarman
- Department of Molecular, Cell and Developmental Biology, Mount Sinai School of Medicine, New York, NY, USA
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Akabane H, Fan J, Zheng X, Zhu GZ. Protein kinase C activity in mouse eggs regulates gamete membrane interaction. Mol Reprod Dev 2007; 74:1465-72. [PMID: 17410540 DOI: 10.1002/mrd.20718] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gamete membrane interaction is critical to initiate the development of a new organism. The signaling pathways governing this event, however, are poorly understood. In this report, we provide the first evidence that protein kinase C activity in mouse eggs plays a crucial role in the regulation of this process. Stimulating PKC activity in mouse eggs by phorbol 12-myristate 13-acetate (PMA) drastically inhibited the egg's membrane ability to bind and fuse with sperm. Surprisingly, this significant reduction of gamete membrane interaction was also observed in eggs treated with the PKC inhibitors staurosporine and calphostin c. In further analysis, we found that while no change of egg actin cytoskeleton was detected after either PMA or calphostin c treatment, the structural morphology of egg surface microvilli was severely altered in the PMA-treated eggs, but not in the calphostin c-treated eggs. Moreover, sperm, which bound but did not fuse with the eggs treated with the anti-CD9 antibody KMC8, were liberated from the egg membrane after PMA, but not calphostin c, treatment. Taken together, these results suggest that egg PKC may be precisely balanced to regulate gamete membrane interaction in a biphasic mode, and this biphasic regulation is executed through two different mechanisms.
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Affiliation(s)
- Hiroto Akabane
- Department of Biological Sciences, Marshall University, Huntington, WV 25755, USA
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Activator-specific requirement of properdin in the initiation and amplification of the alternative pathway complement. Blood 2007; 111:732-40. [PMID: 17916747 DOI: 10.1182/blood-2007-05-089821] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Properdin is a positive regulator of alternative pathway (AP) complement. The current understanding of properdin function is that it facilitates AP complement activation by stabilizing the C3 convertase C3bBb. Properdin-deficient patients are susceptible to lethal meningococcal infection, but the mechanism of this selective predisposition is not fully understood. By gene targeting in the mouse, we show here that properdin is essential for AP complement activation induced by bacterial lipopolysacharride (LPS) and lipooligosacharride (LOS) and other, but not all, AP complement activators. LPS- and LOS-induced AP complement activation was abolished in properdin-/- mouse serum, and properdin-/- mice were unable to clear Crry-deficient erythrocytes, which are known to be susceptible to AP complement-mediated extravascular hemolysis. In contrast, zymosan- and cobra venom factor-induced AP complement activation, and classical pathway-triggered AP complement amplification were only partially or minimally affected in properdin-/- mice. We further show that the ability of human properdin to restore LPS-dependent AP complement activity in properdin-/- mouse serum correlated with the human properdin-binding affinity of the LPS. These results reveal a novel role of properdin in AP complement initiation and have implications for understanding the selective predisposition of properdin-deficient patients to meningococcal infection.
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