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Gilliland WD, May DP, Bowen AO, Conger KO, Elrad D, Marciniak M, Mashburn SA, Presbitero G, Welk LF. A cytological F1 RNAi screen for defects in Drosophila melanogaster female meiosis. Genetics 2024; 227:iyae046. [PMID: 38531678 PMCID: PMC11075555 DOI: 10.1093/genetics/iyae046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 01/11/2024] [Accepted: 03/16/2024] [Indexed: 03/28/2024] Open
Abstract
Genetic screens for recessive alleles induce mutations, make the mutated chromosomes homozygous, and then assay those homozygotes for the phenotype of interest. When screening for genes required for female meiosis, the phenotype of interest has typically been nondisjunction from chromosome segregation errors. As this requires that mutant females be viable and fertile, any mutants that are lethal or sterile when homozygous cannot be recovered by this approach. To overcome these limitations, we have screened the VALIUM22 collection of RNAi constructs that target germline-expressing genes in a vector optimized for germline expression by driving RNAi with GAL4 under control of a germline-specific promoter (nanos or mat-alpha4). This allowed us to test genes that would be lethal if knocked down in all cells, and by examining unfertilized metaphase-arrested mature oocytes, we could identify defects in sterile females. After screening >1,450 lines of the collection for two different defects (chromosome congression and the hypoxic sequestration of Mps1-GFP to ooplasmic filaments), we obtained multiple hits for both phenotypes, identified novel meiotic phenotypes for genes that had been previously characterized in other processes, and identified the first phenotypes to be associated with several previously uncharacterized genes.
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Affiliation(s)
- William D Gilliland
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | - Dennis P May
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | - Amelia O Bowen
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | - Kelly O Conger
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | - Doreen Elrad
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | - Marcin Marciniak
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | - Sarah A Mashburn
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | | | - Lucas F Welk
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
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Gilliland WD, May DP, Bowen AO, Conger KO, Elrad D, Marciniak M, Mashburn SA, Presbitero G, Welk LF. A Cytological F1 RNAi Screen for Defects in Drosophila melanogaster Female Meiosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.575435. [PMID: 38293152 PMCID: PMC10827134 DOI: 10.1101/2024.01.12.575435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Genetic screens for recessive alleles induce mutations, make the mutated chromosomes homozygous, and then assay those homozygotes for the phenotype of interest. When screening for genes required for female meiosis, the phenotype of interest has typically been nondisjunction from chromosome segregation errors. As this requires that mutant females be viable and fertile, any mutants that are lethal or sterile when homozygous cannot be recovered by this approach. To overcome these limitations, our lab has screened the VALIUM22 collection produced by the Harvard TRiP Project, which contains RNAi constructs targeting genes known to be expressed in the germline in a vector optimized for germline expression. By driving RNAi with GAL4 under control of a germline-specific promoter (nanos or mat-alpha4), we can test genes that would be lethal if knocked down in all cells, and by examining unfertilized metaphase-arrested mature oocytes, we can identify defects associated with genes whose knockdown results in sterility or causes other errors besides nondisjunction. We screened this collection to identify genes that disrupt either of two phenotypes when knocked down: the ability of meiotic chromosomes to congress to a single mass at the end of prometaphase, and the sequestration of Mps1-GFP to ooplasmic filaments in response to hypoxia. After screening >1450 lines of the collection, we obtained multiple hits for both phenotypes, identified novel meiotic phenotypes for genes that had been previously characterized in other processes, and identified the first phenotypes to be associated with several previously uncharacterized genes.
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Affiliation(s)
| | | | | | | | - Doreen Elrad
- DePaul University Department of Biological Sciences
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Abstract
The physical connections established by recombination are normally sufficient to ensure proper chromosome segregation during female Meiosis I. However, nonexchange chromosomes (such as the Muller F element or "dot" chromosome in D. melanogaster) can still segregate accurately because they remain connected by heterochromatic tethers. A recent study examined female meiosis in the closely related species D. melanogaster and D. simulans, and found a nearly twofold difference in the mean distance the obligately nonexchange dot chromosomes were separated during Prometaphase. That study proposed two speculative hypotheses for this difference, the first being the amount of heterochromatin in each species, and the second being the species' differing tolerance for common inversions in natural populations. We tested these hypotheses by examining female meiosis in 12 additional Drosophila species. While neither hypothesis had significant support, we did see 10-fold variation in dot chromosome sizes, and fivefold variation in the frequency of chromosomes out on the spindle, which were both significantly correlated with chromosome separation distances. In addition to demonstrating that heterochromatin abundance changes chromosome behavior, this implies that the duration of Prometaphase chromosome movements must be proportional to the size of the F element in these species. Additionally, we examined D. willistoni, a species that lacks a free dot chromosome. We observed that chromosomes still moved out on the meiotic spindle, and the F element was always positioned closest to the spindle poles. This result is consistent with models where one role of the dot chromosomes is to help organize the meiotic spindle.
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Gruhn JR, Zielinska AP, Shukla V, Blanshard R, Capalbo A, Cimadomo D, Nikiforov D, Chan ACH, Newnham LJ, Vogel I, Scarica C, Krapchev M, Taylor D, Kristensen SG, Cheng J, Ernst E, Bjørn AMB, Colmorn LB, Blayney M, Elder K, Liss J, Hartshorne G, Grøndahl ML, Rienzi L, Ubaldi F, McCoy R, Lukaszuk K, Andersen CY, Schuh M, Hoffmann ER. Chromosome errors in human eggs shape natural fertility over reproductive life span. Science 2019; 365:1466-1469. [PMID: 31604276 PMCID: PMC7212007 DOI: 10.1126/science.aav7321] [Citation(s) in RCA: 207] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 09/04/2019] [Indexed: 12/25/2022]
Abstract
Chromosome errors, or aneuploidy, affect an exceptionally high number of human conceptions, causing pregnancy loss and congenital disorders. Here, we have followed chromosome segregation in human oocytes from females aged 9 to 43 years and report that aneuploidy follows a U-curve. Specific segregation error types show different age dependencies, providing a quantitative explanation for the U-curve. Whole-chromosome nondisjunction events are preferentially associated with increased aneuploidy in young girls, whereas centromeric and more extensive cohesion loss limit fertility as women age. Our findings suggest that chromosomal errors originating in oocytes determine the curve of natural fertility in humans.
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Affiliation(s)
- Jennifer R Gruhn
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Agata P Zielinska
- Max Planck Institute for Biophysical Chemistry, Department of Meiosis, Göttingen, Germany
| | - Vallari Shukla
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Robert Blanshard
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
- Illumina Inc., Fulbourn, UK
| | | | - Danilo Cimadomo
- G.en.e.r.a., Centers for Reproductive Medicine, Clinica Valle Giulia, via de notaris 2b, 00197 Rome, Italy
| | - Dmitry Nikiforov
- Laboratory of Reproductive Biology, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Hospital and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Unit of Basic and Applied Biosciences, Università degli studi di Teramo, Teramo, Italy
| | - Andrew Chi-Ho Chan
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Louise J Newnham
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Ivan Vogel
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Catello Scarica
- DAHFMO, Unit of Histology and Medical Embryology, Sapienza, University of Rome, Italy
| | - Marta Krapchev
- INVICTA Fertility and Reproductive Center, Gdańsk, Poland
| | - Deborah Taylor
- Warwick Medical School, University of Warwick and Centre for Reproductive Medicine, University Hospital Coventry, UK
| | - Stine Gry Kristensen
- Laboratory of Reproductive Biology, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Hospital and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Junping Cheng
- Laboratory of Reproductive Biology, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Hospital and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Erik Ernst
- Department of Obstetrics and Gynaecology, University Hospital of Aarhus, Skejby Sygehus, Aarhus, Denmark
| | - Anne-Mette Bay Bjørn
- Department of Obstetrics and Gynaecology, University Hospital of Aarhus, Skejby Sygehus, Aarhus, Denmark
| | - Lotte Berdiin Colmorn
- The Fertility Clinic, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Rigshospitalet, Denmark
| | | | | | - Joanna Liss
- INVICTA Fertility and Reproductive Center, Gdańsk, Poland
- Department of Biology and Medical Genetics, University of Gdańsk, Gdańsk, Poland
| | - Geraldine Hartshorne
- Warwick Medical School, University of Warwick and Centre for Reproductive Medicine, University Hospital Coventry, UK
| | - Marie Louise Grøndahl
- Department of Obstetrics and Gynaecology, Department of Reproductive Medicine, Copenhagen University Hospital Herlev, Denmark
| | - Laura Rienzi
- G.en.e.r.a., Centers for Reproductive Medicine, Clinica Valle Giulia, via de notaris 2b, 00197 Rome, Italy
| | - Filippo Ubaldi
- G.en.e.r.a., Centers for Reproductive Medicine, Clinica Valle Giulia, via de notaris 2b, 00197 Rome, Italy
| | - Rajiv McCoy
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Krzysztof Lukaszuk
- INVICTA Fertility and Reproductive Center, Gdańsk, Poland
- Department of Obstetrics and Gynaecological Nursing, Faculty of Health Sciences, Medical University of Gdańsk, Gdańsk, Poland
- Department of Gynaecological Endocrinology, Medical University of Warsaw, Warsaw, Poland
| | - Claus Yding Andersen
- Laboratory of Reproductive Biology, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Hospital and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Melina Schuh
- Max Planck Institute for Biophysical Chemistry, Department of Meiosis, Göttingen, Germany
| | - Eva R Hoffmann
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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Buchman A, Akbari OS. Site-specific transgenesis of the Drosophila melanogaster Y-chromosome using CRISPR/Cas9. INSECT MOLECULAR BIOLOGY 2019; 28:65-73. [PMID: 30079589 PMCID: PMC8459378 DOI: 10.1111/imb.12528] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite the importance of Y-chromosomes in evolution and sex determination, their heterochromatic, repeat-rich nature makes them difficult to sequence (due, in part, to ambiguities in sequence alignment and assembly) and to genetically manipulate. Therefore, they generally remain poorly understood. For example, the Drosophila melanogaster Y-chromosome, one of the most extensively studied Y-chromosomes, is widely heterochromatic and composed mainly of highly repetitive sequences, with only a handful of expressed genes scattered throughout its length. Efforts to insert transgenes on this chromosome have thus far relied on either random insertion of transposons (sometimes harbouring 'landing sites' for subsequent integrations) with limited success or on chromosomal translocations, thereby limiting the types of Y-chromosome-related questions that could be explored. Here, we describe a versatile approach to site-specifically insert transgenes on the Y-chromosome in D. melanogaster via CRISPR/Cas9-mediated homology-directed repair. We demonstrate the ability to insert, and detect expression from, fluorescently marked transgenes at two specific locations on the Y-chromosome, and we utilize these marked Y-chromosomes to detect and quantify rare chromosomal nondisjunction effects. Finally, we discuss how this Y-docking technique could be adapted to other insects to aid in the development of genetic control technologies for the management of insect disease vectors and pests.
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Affiliation(s)
- Anna Buchman
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, 92093, United States of America
| | - Omar S. Akbari
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, 92093, United States of America
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA 92093, United States of America
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Female Meiosis: Synapsis, Recombination, and Segregation in Drosophila melanogaster. Genetics 2018; 208:875-908. [PMID: 29487146 PMCID: PMC5844340 DOI: 10.1534/genetics.117.300081] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/18/2017] [Indexed: 12/11/2022] Open
Abstract
A century of genetic studies of the meiotic process in Drosophila melanogaster females has been greatly augmented by both modern molecular biology and major advances in cytology. These approaches, and the findings they have allowed, are the subject of this review. Specifically, these efforts have revealed that meiotic pairing in Drosophila females is not an extension of somatic pairing, but rather occurs by a poorly understood process during premeiotic mitoses. This process of meiotic pairing requires the function of several components of the synaptonemal complex (SC). When fully assembled, the SC also plays a critical role in maintaining homolog synapsis and in facilitating the maturation of double-strand breaks (DSBs) into mature crossover (CO) events. Considerable progress has been made in elucidating not only the structure, function, and assembly of the SC, but also the proteins that facilitate the formation and repair of DSBs into both COs and noncrossovers (NCOs). The events that control the decision to mature a DSB as either a CO or an NCO, as well as determining which of the two CO pathways (class I or class II) might be employed, are also being characterized by genetic and genomic approaches. These advances allow a reconsideration of meiotic phenomena such as interference and the centromere effect, which were previously described only by genetic studies. In delineating the mechanisms by which the oocyte controls the number and position of COs, it becomes possible to understand the role of CO position in ensuring the proper orientation of homologs on the first meiotic spindle. Studies of bivalent orientation have occurred in the context of numerous investigations into the assembly, structure, and function of the first meiotic spindle. Additionally, studies have examined the mechanisms ensuring the segregation of chromosomes that have failed to undergo crossing over.
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