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Vedelek V, Jankovics F, Zádori J, Sinka R. Mitochondrial Differentiation during Spermatogenesis: Lessons from Drosophila melanogaster. Int J Mol Sci 2024; 25:3980. [PMID: 38612789 PMCID: PMC11012351 DOI: 10.3390/ijms25073980] [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: 02/06/2024] [Revised: 03/22/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Numerous diseases can arise as a consequence of mitochondrial malfunction. Hence, there is a significant focus on studying the role of mitochondria in cancer, ageing, neurodegenerative diseases, and the field of developmental biology. Mitochondria could exist as discrete organelles in the cell; however, they have the ability to fuse, resulting in the formation of interconnected reticular structures. The dynamic changes between these forms correlate with mitochondrial function and mitochondrial health, and consequently, there is a significant scientific interest in uncovering the specific molecular constituents that govern these transitions. Moreover, the specialized mitochondria display a wide array of variable morphologies in their cristae formations. These inner mitochondrial structures are closely associated with the specific functions performed by the mitochondria. In multiple cases, the presence of mitochondrial dysfunction has been linked to male sterility, as it has been observed to cause a range of abnormal spermatogenesis and sperm phenotypes in different species. This review aims to elucidate the dynamic alterations and functions of mitochondria in germ cell development during the spermatogenesis of Drosophila melanogaster.
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Affiliation(s)
- Viktor Vedelek
- Department of Genetics, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary
| | - Ferenc Jankovics
- Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary;
- Department of Medical Biology, Albert Szent-Györgyi Medical Centre, University of Szeged, 6720 Szeged, Hungary
| | - János Zádori
- Institute of Reproductive Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged, 6723 Szeged, Hungary;
| | - Rita Sinka
- Department of Genetics, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary
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Kimura S, Loppin B. Two bromodomain proteins functionally interact to recapitulate an essential BRDT-like function in Drosophila spermatocytes. Open Biol 2015; 5:140145. [PMID: 25652540 PMCID: PMC4345279 DOI: 10.1098/rsob.140145] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In mammals, the testis-specific bromodomain and extra terminal (BET) protein BRDT is essential for spermatogenesis. In Drosophila, it was recently reported that the tBRD-1 protein is similarly required for male fertility. Interestingly, however, tBRD-1 has two conserved bromodomains in its N-terminus but it lacks an extra terminal (ET) domain characteristic of BET proteins. Here, using proteomics approaches to search for tBRD-1 interactors, we identified tBRD-2 as a novel testis-specific bromodomain protein. In contrast to tBRD-1, tBRD-2 contains a single bromodomain, but which is associated with an ET domain in its C-terminus. Strikingly, we show that tbrd-2 knock-out males are sterile and display aberrant meiosis in a way highly similar to tbrd-1 mutants. Furthermore, these two factors co-localize and are interdependent in spermatocytes. We propose that Drosophila tBRD-1 and tBRD-2 associate into a functional BET complex in spermatocytes, which recapitulates the activity of the single mammalian BRDT-like protein.
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Affiliation(s)
- Shuhei Kimura
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR5534, Université Claude Bernard Lyon 1, 69622 Villeurbanne cedex, France
| | - Benjamin Loppin
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR5534, Université Claude Bernard Lyon 1, 69622 Villeurbanne cedex, France
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Shapiro-Kulnane L, Smolko AE, Salz HK. Maintenance of Drosophila germline stem cell sexual identity in oogenesis and tumorigenesis. Development 2015; 142:1073-82. [PMID: 25758221 DOI: 10.1242/dev.116590] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Adult stem cells maintain tissue homeostasis by balancing self-renewal and differentiation. In Drosophila females, germline stem cells (GSCs) require Sex lethal (Sxl) to exit the stem cell state and to enter the differentiation pathway. Without Sxl GSCs do not differentiate and instead form tumors. Previous studies have shown that these tumors are not caused by a failure in the self-renewal/differentiation switch. Here, we show that Sxl is also necessary for the cell-autonomous maintenance of germ cell female identity and demonstrate that tumors are caused by the acquisition of male characteristics. Germ cells without Sxl protein exhibit a global derepression of testis genes, including Phf7, a male germline sexual identity gene. Phf7 is a key effector of the tumor-forming pathway, as it is both necessary and sufficient for tumor formation. In the absence of Sxl protein, inappropriate Phf7 expression drives tumor formation through a cell-autonomous mechanism that includes sex-inappropriate activation of Jak/Stat signaling. Remarkably, tumor formation requires a novel response to external signals emanating from the GSC niche, highlighting the importance of interactions between mutant cells and the surrounding normal cells that make up the tumor microenvironment. Derepression of testis genes, and inappropriate Phf7 expression, is also observed in germ cell tumors arising from the loss of bag of marbles (bam), demonstrating that maintenance of female sexual identity requires the concerted actions of Sxl and bam. Our work reveals that GSCs must maintain their sexual identity as they are reprogrammed into a differentiated cell, or risk tumorigenesis.
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Affiliation(s)
- Laura Shapiro-Kulnane
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4955, USA
| | - Anne Elizabeth Smolko
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4955, USA
| | - Helen Karen Salz
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4955, USA
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Sekiné K, Furusawa T, Hatakeyama M. The boule gene is essential for spermatogenesis of haploid insect male. Dev Biol 2015; 399:154-163. [PMID: 25592223 DOI: 10.1016/j.ydbio.2014.12.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/18/2014] [Accepted: 12/22/2014] [Indexed: 11/15/2022]
Abstract
boule (bol), a member of the Deleted in Azoospermia (DAZ) gene family plays an important role in meiosis (reductional maturation divisions) in a spermatogenesis-specific manner in animals by regulating translation of the downstream cell division cycle 25 (cdc25) phosphatase mRNA. Orthologues of bol are conserved among animals and found in the genomes of hymenopteran insects, in which the general mode of reproduction is haplodiploidy: female is diploid and male is haploid. In this mode of reproduction, haploid males produce haploid sperm through non-reductional maturation divisions. The question thus arises of whether the bol gene actually functions during spermatogenesis in these haploid males. In this study, we identified two transcriptional isoforms of bol orthologue (Ar bol and Ar bol-2), and one cdc25 orthologue (Ar cdc25) in the hymenopteran sawfly, Athalia rosae. Ar bol was expressed exclusively in the testis when maturation divisions occurred, while Ar bol-2 was expressed ubiquitously. Knockdown of all bol transcripts (both Ar bol and Ar bol-2) resulted in a lack of mature sperm, whereas males with sole knockdown of Ar bol-2 were able to produce a small number of mature sperm. The cell cycle was arrested before maturation divisions in the testis in which all bol transcripts were knocked down, as revealed by flow cytometry. Although no mature sperm was produced, sperm elongation was partially observed when Ar cdc25 alone was knocked down. These results indicate that Ar bol is essential for the entry and progression of maturation divisions and sperm differentiation in haploid males.
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Affiliation(s)
- Kazuki Sekiné
- Division of Insect Sciences, National Institute of Agrobiological Sciences, 1-2, Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Tadashi Furusawa
- Division of Animal Sciences, National Institute of Agrobiological Sciences, 2, Ikenodai, Tsukuba, Ibaraki 305-8602, Japan
| | - Masatsugu Hatakeyama
- Division of Insect Sciences, National Institute of Agrobiological Sciences, 1-2, Owashi, Tsukuba, Ibaraki 305-8634, Japan.
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Giansanti MG, Sechi S, Frappaolo A, Belloni G, Piergentili R. Cytokinesis in Drosophila male meiosis. SPERMATOGENESIS 2014; 2:185-196. [PMID: 23094234 PMCID: PMC3469441 DOI: 10.4161/spmg.21711] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cytokinesis separates the cytoplasm and the duplicated genome into two daughter cells at the end of cell division. This process must be finely regulated to maintain ploidy and prevent tumor formation. Drosophila male meiosis provides an excellent cell system for investigating cytokinesis. Mutants affecting this process can be easily identified and spermatocytes are large cells particularly suitable for cytological analysis of cytokinetic structures. Over the past decade, the powerful tools of Drosophila genetics and the unique characteristics of this cell system have led researchers to identify molecular players of the cell cleavage machinery and to address important open questions. Although spermatocyte cytokinesis is incomplete, resulting in formation of stable intercellular bridges, the molecular mechanisms are largely conserved in somatic cells. Thus, studies of Drosophila male meiosis will shed new light on the complex cell circuits regulating furrow ingression and substantially further our knowledge of cancer and other human diseases.
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Affiliation(s)
- Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR; Dipartimento di Biologia e Biotecnologie Università Sapienza di Roma; Rome, Italy
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Leser K, Awe S, Barckmann B, Renkawitz-Pohl R, Rathke C. The bromodomain-containing protein tBRD-1 is specifically expressed in spermatocytes and is essential for male fertility. Biol Open 2012; 1:597-606. [PMID: 23213453 PMCID: PMC3509448 DOI: 10.1242/bio.20121255] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
By a conserved cellular differentiation process, spermatogenesis leads to formation of haploid sperm for successful reproduction. In Drosophila and in mammals, post-meiotic spermatid differentiation depends on several translationally repressed and stored mRNAs that are often expressed exclusively in the testis through a cell type specific transcriptional program. In Drosophila, the mRNAs of proteins required for post-meiotic chromatin reorganisation, like ProtB and Mst77F, are transcribed in meiotic spermatocytes and subjected to translational repression for days. Transcription of many of these translationally repressed mRNAs depends on testis-specific homologs of TATA box binding protein-associated factors (tTAFs). Here, we identified the testis-specific bromodomain protein, tBRD-1, that is only expressed in primary spermatocytes. Bromodomain proteins are able to recognise and bind acetylated histones and non-histone proteins. We generated tbrd-1 mutant flies and observed that function of tBRD-1 is required for male fertility. tBRD-1 partially colocalised with tTAFs, TAF1 and Polycomb to a Fibrillarin-deficient region within the spermatocyte nucleolus. The nucleolar localisation of tBRD-1 depended on tTAF function but not the other way round. Further, we could show that ectopically expressed tBRD-1-eGFP is able to bind to the interbands of polytene chromosomes. By inhibitor treatment of cultured testis we observed that sub-cellular localisation of tBRD-1 may depend on the acetylation status of primary spermatocytes.
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Affiliation(s)
- Katja Leser
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie , Karl-von-Frisch Strasse 8, 35043 Marburg , Germany
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Edlinger B, Schlögelhofer P. Have a break: determinants of meiotic DNA double strand break (DSB) formation and processing in plants. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:1545-63. [PMID: 21220780 DOI: 10.1093/jxb/erq421] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Meiosis is an essential process for sexually reproducing organisms, leading to the formation of specialized generative cells. This review intends to highlight current knowledge of early events during meiosis derived from various model organisms, including plants. It will particularly focus on cis- and trans-requirements of meiotic DNA double strand break (DSB) formation, a hallmark event during meiosis and a prerequisite for recombination of genetic traits. Proteins involved in DSB formation in different organisms, emphasizing the known factors from plants, will be introduced and their functions outlined. Recent technical advances in DSB detection and meiotic recombination analysis will be reviewed, as these new tools now allow analysis of early meiotic recombination in plants with incredible accuracy. To anticipate future directions in plant meiosis research, unpublished results will be included wherever possible.
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Affiliation(s)
- Bernd Edlinger
- University of Vienna, Max F. Perutz Laboratories, Department of Chromosome Biology, Dr. Bohr-Gasse 1, Vienna, Austria
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Abstract
The perpetuation of most eukaryotic species requires differentiation of pluripotent progenitors into egg and sperm and subsequent fusion of these gametes to form a new zygote. Meiosis is a distinguishing feature of gamete formation as it leads to the twofold reduction in chromosome number thereby maintaining ploidy across generations. This process increases offspring diversity through the random segregation of chromosomes and the exchange of genetic material between homologous parental chromosomes, known as meiotic crossover recombination. These exchanges require the establishment of unique and dynamic chromatin configurations that facilitate cohesion, homolog pairing, synapsis, double strand break formation and repair. The precise orchestration of these events is critical for gamete survival as demonstrated by the majority of human aneuploidies that can be traced to defects in the first meiotic division (Hassold T, Hall H, Hunt P: The origin of human aneuploidy: where we have been, where we are going. Hum Mol Genet 2007, 16 Spec No. 2:R203-R208.). This review will focus on recent advances in our understanding of key meiotic events and how coordination of these events is occurring.
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Affiliation(s)
- Judith Yanowitz
- Magee-Womens Research Institute, 204 Craft Avenue, Pittsburgh, PA 15213, USA.
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