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Zhang R, Shi P, Xu S, Ming Z, Liu Z, He Y, Dai J, Matunis E, Xu J, Ma Q. Soma-germline communication drives sex maintenance in the Drosophila testis. Natl Sci Rev 2024; 11:nwae215. [PMID: 39183747 PMCID: PMC11342250 DOI: 10.1093/nsr/nwae215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/08/2024] [Accepted: 06/09/2024] [Indexed: 08/27/2024] Open
Abstract
In adult gonads, disruption of somatic sexual identity leads to defective gametogenesis and infertility. However, the underlying mechanisms by which somatic signals regulate germline cells to achieve proper gametogenesis remain unclear. In our previous study, we introduced the chinmoSex Transformation (chinmoST ) mutant Drosophila testis phenotype as a valuable model for investigating the mechanisms underlying sex maintenance. In chinmoST testes, depletion of the Janus Kinase-Signal Transducer and Activator of Transcription downstream effector Chinmo from somatic cyst stem cells (CySCs) feminizes somatic cyst cells and arrests germline differentiation. Here, we use single-cell RNA sequencing to uncover chinmoST -specific cell populations and their transcriptomic changes during sex transformation. Comparative analysis of intercellular communication networks between wild-type and chinmoST testes revealed disruptions in several soma-germline signaling pathways in chinmoST testes. Notably, the insulin signaling pathway exhibited significant enhancement in germline stem cells (GSCs). Chinmo cleavage under targets and tagmentation (CUT&Tag) assay revealed that Chinmo directly regulates two male sex determination factors, doublesex (dsx) and fruitless (fru), as well as Ecdysone-inducible gene L2 (ImpL2), a negative regulator of the insulin signaling pathway. Further genetic manipulations confirmed that the impaired gametogenesis observed in chinmoST testes was partly contributed by dysregulation of the insulin signaling pathway. In summary, our study demonstrates that somatic sex maintenance promotes normal spermatogenesis through Chinmo-mediated conserved sex determination and the insulin signaling pathway. Our work offers new insights into the complex mechanisms of somatic stem cell sex maintenance and soma-germline communication at the single-cell level. Additionally, our discoveries highlight the potential significance of stem cell sex instability as a novel mechanism contributing to testicular tumorigenesis.
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Affiliation(s)
- Rui Zhang
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Peiyu Shi
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Shuyang Xu
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Zhe Ming
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Zicong Liu
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yuanyuan He
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Junbiao Dai
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Erika Matunis
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jin Xu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Qing Ma
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
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Rinehart L, Stewart WE, Luffman N, Wawersik M, Kerscher O. Chigno/CG11180 and SUMO are Chinmo-interacting proteins with a role in Drosophila testes somatic support cells. PeerJ 2024; 12:e16971. [PMID: 38495765 PMCID: PMC10944633 DOI: 10.7717/peerj.16971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/29/2024] [Indexed: 03/19/2024] Open
Abstract
Stem cells are critical for replenishment of cells lost to death, damage or differentiation. Drosophila testes are a key model system for elucidating mechanisms regulating stem cell maintenance and differentiation. An intriguing gene identified through such studies is the transcription factor, chronologically inappropriate morphogenesis (Chinmo). Chinmo is a downstream effector of the Jak-STAT signaling pathway that acts in testis somatic stem cells to ensure maintenance of male stem cell fate and sexual identity. Defects in these processes can lead to infertility and the formation of germ cell tumors. While Chinmo's effect on testis stem cell behavior has been investigated in detail, there is still much to be learned about its structure, function, and interactions with other proteins. Using a two-hybrid screen, we find that Chinmo interacts with itself, the small ubiquitin-like modifier SUMO, the novel protein CG11180, and four other proteins (CG4318, Ova (ovaries absent), Taf3 (TBP-associated factor 3), and CG18269). Since both Chinmo and CG11180 contain sumoylation sites and SUMO-interacting motifs (SIMs), we analyzed their interaction in more detail. Using site-directed mutagenesis of a unique SIM in CG11180, we demonstrate that Chinmo's interaction with CG11180 is SUMO-dependent. Furthermore, to assess the functional relevance of both SUMO and CG11180, we performed RNAi-mediated knockdown of both proteins in somatic cells of the Drosophila testis. Using this approach, we find that CG11180 and SUMO are required in somatic cells of adult testes, and that reduction of either protein causes formation of germ cell tumors. Overall, our work suggests that SUMO may be involved in the interaction of Chinmo and CG11180 and that these genes are required in somatic cells of the adult Drosophila testis. Consistent with the CG11180 knockdown phenotype in male testes, and to underscore its connection to Chinmo, we propose the name Chigno (Childless Gambino) for CG11180.
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Affiliation(s)
- Leanna Rinehart
- Biology Department, William & Mary, Williamsburg, VA, United States of America
| | - Wendy E. Stewart
- Biology Department, William & Mary, Williamsburg, VA, United States of America
| | - Natalie Luffman
- Biology Department, William & Mary, Williamsburg, VA, United States of America
| | - Matthew Wawersik
- Biology Department, William & Mary, Williamsburg, VA, United States of America
| | - Oliver Kerscher
- Biology Department, William & Mary, Williamsburg, VA, United States of America
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Swanson GM, Estill MS, Krawetz SA. The transcript integrity index (TII) provides a standard measure of sperm RNA. Syst Biol Reprod Med 2022; 68:258-271. [PMID: 35658756 DOI: 10.1080/19396368.2022.2071133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Standardizing RNA quality is key to interpreting RNA-seq data as a compromised sample can mask the underlying biology. The challenge remains when evaluating RNA quality in samples with high RNA fragmentation. For example, programmed fragmentation and cytoplasmic expulsion, integral to sperm maturation, is a prime example of the complexities of interpreting RNA-seq data, given that fragmentation can be random and\or targeted. To meet this challenge, we developed an algorithm that accurately measures RNA quality in samples with high fragmentation, such as spermatozoa. The integrity of 1,000 previously identified abundant sperm transcripts were independently visualized and evaluated using the Transcript Integrity Index (TII) algorithm to identify intact transcripts. Full-length transcripts from visual and the TII algorithm were evaluated for testis preference in humans using the GTEx tissues database. Samples were then filtered by the Interquartile Range (IQR), identifying those in which the greatest number of transcripts failed to pass the visual or TII thresholds. Transcript lists were overlapped, forming the set of intact transcripts used as TII standards. Each sample was re-evaluated as a function of this TII set of intact transcripts, with poor quality samples identified as those failing in the largest number of transcripts. While ontologically enriched in roles related to spermatogenesis and/or fertilization, samples did not segregate based on birth outcome. The TII algorithm proved an effective means to identify samples of similar quality from sperm, a cell type enriched in biologically fragmented RNAs. The algorithm should facilitate other studies using samples compromised by high levels of RNA fragmentation, such as Formalin-Fixed Paraffin-Embedded samples. Requisite to assessing male health, TII provides a solution to the long-sought-after standard that identifies samples of similar quality.
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Affiliation(s)
- Grace M Swanson
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.,Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Molly S Estill
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stephen A Krawetz
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.,Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
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4
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Connecting Ras and CTP synthase in Drosophila. Exp Cell Res 2022; 416:113155. [DOI: 10.1016/j.yexcr.2022.113155] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/03/2022] [Accepted: 04/08/2022] [Indexed: 11/04/2022]
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Zinshteyn D, Barbash DA. Stonewall prevents expression of ectopic genes in the ovary and accumulates at insulator elements in D. melanogaster. PLoS Genet 2022; 18:e1010110. [PMID: 35324887 PMCID: PMC8982855 DOI: 10.1371/journal.pgen.1010110] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 04/05/2022] [Accepted: 02/18/2022] [Indexed: 11/29/2022] Open
Abstract
Germline stem cells (GSCs) are the progenitor cells of the germline for the lifetime of an animal. In Drosophila, these cells reside in a cellular niche that is required for both their maintenance (self-renewal) and differentiation (asymmetric division resulting in a daughter cell that differs from the GSC). The stem cell—daughter cell transition is tightly regulated by a number of processes, including an array of proteins required for genome stability. The germline stem-cell maintenance factor Stonewall (Stwl) associates with heterochromatin, but its molecular function is poorly understood. We performed RNA-Seq on stwl mutant ovaries and found significant derepression of many transposon families but not heterochromatic genes. We also discovered inappropriate expression of multiple classes of genes. Most prominent are testis-enriched genes, including the male germline sex-determination switch Phf7, the differentiation factor bgcn, and a large testis-specific gene cluster on chromosome 2, all of which are upregulated or ectopically expressed in stwl mutant ovaries. Surprisingly, we also found that RNAi knockdown of stwl in somatic S2 cells results in ectopic expression of these testis genes. Using parallel ChIP-Seq and RNA-Seq experiments in S2 cells, we discovered that Stwl localizes upstream of transcription start sites and at heterochromatic sequences including repetitive sequences associated with telomeres. Stwl is also enriched at bgcn, suggesting that it directly regulates this essential differentiation factor. Finally, we identify Stwl binding motifs that are shared with known insulator binding proteins. We propose that Stwl affects gene regulation, including repression of male transcripts in the female germline, by binding insulators and establishing chromatin boundaries. Stem cells are defined by their ability to divide asymmetrically, resulting in a differentiated cell and a stem cell daughter. In fruit flies, sperm and egg production begins with germline stem cells (GSCs). The ability of a GSC to differentiate or self-renew is tightly regulated by a myriad of factors. Some of these are transcription factors, which are responsible for activating or suppressing other genes to promote one state in favor of another. Stonewall is an ovarian nuclear protein required for GSC self-renewal, whose molecular function is poorly understood. Here we show that Stonewall is responsible for preventing the activation of “male” molecular programming in the fruit fly ovary. When Stonewall is absent from the ovary, egg production is terminated and testis-specific genes become highly expressed, including the male transcript of Phf7, which induces male sexual identity in female germ cells. We also show that Stonewall is likely localizing to genomic insulators, which are regions of the genome that shield genes from nearby regulators. Our findings suggest that Stonewall helps to organize the genome in ovarian germ cells and prevent expression of male genes.
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Affiliation(s)
- Daniel Zinshteyn
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Daniel A. Barbash
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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Carty BL, Dattoli AA, Dunleavy EM. CENP-C functions in centromere assembly, the maintenance of CENP-A asymmetry and epigenetic age in Drosophila germline stem cells. PLoS Genet 2021; 17:e1009247. [PMID: 34014920 PMCID: PMC8136707 DOI: 10.1371/journal.pgen.1009247] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/16/2021] [Indexed: 01/08/2023] Open
Abstract
Germline stem cells divide asymmetrically to produce one new daughter stem cell and one daughter cell that will subsequently undergo meiosis and differentiate to generate the mature gamete. The silent sister hypothesis proposes that in asymmetric divisions, the selective inheritance of sister chromatids carrying specific epigenetic marks between stem and daughter cells impacts cell fate. To facilitate this selective inheritance, the hypothesis specifically proposes that the centromeric region of each sister chromatid is distinct. In Drosophila germ line stem cells (GSCs), it has recently been shown that the centromeric histone CENP-A (called CID in flies)—the epigenetic determinant of centromere identity—is asymmetrically distributed between sister chromatids. In these cells, CID deposition occurs in G2 phase such that sister chromatids destined to end up in the stem cell harbour more CENP-A, assemble more kinetochore proteins and capture more spindle microtubules. These results suggest a potential mechanism of ‘mitotic drive’ that might bias chromosome segregation. Here we report that the inner kinetochore protein CENP-C, is required for the assembly of CID in G2 phase in GSCs. Moreover, CENP-C is required to maintain a normal asymmetric distribution of CID between stem and daughter cells. In addition, we find that CID is lost from centromeres in aged GSCs and that a reduction in CENP-C accelerates this loss. Finally, we show that CENP-C depletion in GSCs disrupts the balance of stem and daughter cells in the ovary, shifting GSCs toward a self-renewal tendency. Ultimately, we provide evidence that centromere assembly and maintenance via CENP-C is required to sustain asymmetric divisions in female Drosophila GSCs. Stem cells can divide in an asymmetric fashion giving rise to two daughter cells with different fates. One daughter remains a stem cell, while the other can differentiate and adopt a new cell fate. Germline stem cells in the testes and ovaries give rise to differentiating daughter cells that eventually form the gametes, eggs and sperm. Here we investigate mechanisms controlling germline stem cell divisions occurring in the ovary of the fruit fly Drosophila melanogaster. Centromeres are epigenetically specified loci on chromosomes that make essential connections to the cell division machinery. Our study is focused on the centromere component CENP-C. We show that CENP-C is critical for the correct assembly of centromeres that occurs prior to cell division in germline stem cells. In addition, we find that CENP-C is asymmetrically distributed between stem and daughter cells, with more CENP-C at stem cell centromeres. Finally, we show that CENP-C depletion in germline stem cells disrupts the balance of stem and daughter cells in the developing ovary, impacting on cell fate. Taken together, we propose that CENP-C level and function at centromeres plays an important role in determining cell fate upon asymmetric division occurring in stem cells.
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Affiliation(s)
- Ben L. Carty
- Centre for Chromosome Biology, Biomedical Sciences, National University of Ireland Galway, Galway, Ireland
| | - Anna A. Dattoli
- Centre for Chromosome Biology, Biomedical Sciences, National University of Ireland Galway, Galway, Ireland
| | - Elaine M. Dunleavy
- Centre for Chromosome Biology, Biomedical Sciences, National University of Ireland Galway, Galway, Ireland
- * E-mail:
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Smolko AE, Shapiro-Kulnane L, Salz HK. An autoregulatory switch in sex-specific phf7 transcription causes loss of sexual identity and tumors in the Drosophila female germline. Development 2020; 147:dev.192856. [PMID: 32816970 DOI: 10.1242/dev.192856] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/07/2020] [Indexed: 12/22/2022]
Abstract
Maintenance of germ cell sexual identity is essential for reproduction. Entry into the spermatogenesis or oogenesis pathway requires that the appropriate gene network is activated and the antagonist network is silenced. For example, in Drosophila female germ cells, forced expression of the testis-specific PHD finger protein 7 (PHF7) disrupts oogenesis, leading to either an agametic or germ cell tumor phenotype. Here, we show that PHF7-expressing ovarian germ cells inappropriately express hundreds of genes, many of which are male germline genes. We find that the majority of genes under PHF7 control in female germ cells are not under PHF7 control in male germ cells, suggesting that PHF7 is acting in a tissue-specific manner. Remarkably, transcriptional reprogramming includes a positive autoregulatory feedback mechanism in which ectopic PHF7 overcomes its own transcriptional repression through promoter switching. Furthermore, we find that tumorigenic capacity is dependent on the dosage of phf7 This study reveals that ectopic PHF7 in female germ cells leads to a loss of sexual identity and the promotion of a regulatory circuit that is beneficial for tumor initiation and progression.
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Affiliation(s)
- Anne E Smolko
- Department of Genetics and Genome Sciences, Case Western Reserve University, School of Medicine, Cleveland, OH 44106-4955, USA
| | - Laura Shapiro-Kulnane
- Department of Genetics and Genome Sciences, Case Western Reserve University, School of Medicine, Cleveland, OH 44106-4955, USA
| | - Helen K Salz
- Department of Genetics and Genome Sciences, Case Western Reserve University, School of Medicine, Cleveland, OH 44106-4955, USA
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Predicting Gonadal Germ Cell Cancer in People with Disorders of Sex Development; Insights from Developmental Biology. Int J Mol Sci 2019; 20:ijms20205017. [PMID: 31658757 PMCID: PMC6834166 DOI: 10.3390/ijms20205017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/03/2019] [Accepted: 10/05/2019] [Indexed: 01/03/2023] Open
Abstract
The risk of gonadal germ cell cancer (GGCC) is increased in selective subgroups, amongst others, defined patients with disorders of sex development (DSD). The increased risk is due to the presence of part of the Y chromosome, i.e., GonadoBlastoma on Y chromosome GBY region, as well as anatomical localization and degree of testicularization and maturation of the gonad. The latter specifically relates to the germ cells present being at risk when blocked in an embryonic stage of development. GGCC originates from either germ cell neoplasia in situ (testicular environment) or gonadoblastoma (ovarian-like environment). These precursors are characterized by presence of the markers OCT3/4 (POU5F1), SOX17, NANOG, as well as TSPY, and cKIT and its ligand KITLG. One of the aims is to stratify individuals with an increased risk based on other parameters than histological investigation of a gonadal biopsy. These might include evaluation of defined susceptibility alleles, as identified by Genome Wide Association Studies, and detailed evaluation of the molecular mechanism underlying the DSD in the individual patient, combined with DNA, mRNA, and microRNA profiling of liquid biopsies. This review will discuss the current opportunities as well as limitations of available knowledge in the context of predicting the risk of GGCC in individual patients.
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Saavedra P, Perrimon N. Drosophila as a Model for Tumor-Induced Organ Wasting. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1167:191-205. [PMID: 31520356 DOI: 10.1007/978-3-030-23629-8_11] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In humans, cancer-associated cachexia is a complex syndrome that reduces the overall quality of life and survival of cancer patients, particularly for those undergoing chemotherapy. The most easily observable sign of cachexia is organ wasting, the dramatic loss of skeletal muscle and adipose tissue mass. Estimates suggest that 80% of patients in advanced stages of cancer show signs of the syndrome and about 20% of cancer patients die directly of cachexia. Because there is no treatment or drug available to ameliorate organ wasting induced by cancer, cachexia is a relevant clinical problem. However, it is unclear how cachexia is mediated, what factors drive interactions between tumors and host tissues, and which markers of cachexia might be used to allow early detection before the observable signs of organ wasting. In this chapter, we review the current mammalian models of cachexia and the need to use new models of study. We also explain recent developments in Drosophila as a model for studying organ wasting induced by tumors and how fly studies can help unravel important mechanisms that drive cachexia. In particular, we discuss what lessons have been learned from tumor models recently reported to induce systemic organ wasting in Drosophila.
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Affiliation(s)
- Pedro Saavedra
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA. .,Howard Hughes Medical Institute, Boston, MA, USA.
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The H3K9 methyltransferase SETDB1 maintains female identity in Drosophila germ cells. Nat Commun 2018; 9:4155. [PMID: 30297796 PMCID: PMC6175928 DOI: 10.1038/s41467-018-06697-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 09/19/2018] [Indexed: 12/17/2022] Open
Abstract
The preservation of germ cell sexual identity is essential for gametogenesis. Here we show that H3K9me3-mediated gene silencing is integral to female fate maintenance in Drosophila germ cells. Germ cell specific loss of the H3K9me3 pathway members, the H3K9 methyltransferase SETDB1, WDE, and HP1a, leads to ectopic expression of genes, many of which are normally expressed in testis. SETDB1 controls the accumulation of H3K9me3 over a subset of these genes without spreading into neighboring loci. At phf7, a regulator of male germ cell sexual fate, the H3K9me3 peak falls over the silenced testis-specific transcription start site. Furthermore, H3K9me3 recruitment to phf7 and repression of testis-specific transcription is dependent on the female sex determination gene Sxl. Thus, female identity is secured by an H3K9me3 epigenetic pathway in which Sxl is the upstream female-specific regulator, SETDB1 is the required chromatin writer, and phf7 is one of the critical SETDB1 target genes. Epigenetic regulation is critical for the maintenance of germ cell identity. Here the authors show that H3K9me3-mediated gene silencing is critical for repression of testis-specific transcription in Drosophila female germ cells, indicating H3K9me3 maintains female germ cell sexual identity.
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The Vertebrate Protein Dead End Maintains Primordial Germ Cell Fate by Inhibiting Somatic Differentiation. Dev Cell 2017; 43:704-715.e5. [DOI: 10.1016/j.devcel.2017.11.019] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/14/2017] [Accepted: 11/20/2017] [Indexed: 12/14/2022]
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