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Heaney J, Zhao J, Casagranda F, Loveland KL, Siddall NA, Hime GR. Drosophila Importin Alpha 1 (Dα1) Is Required to Maintain Germline Stem Cells in the Testis Niche. Cells 2024; 13:494. [PMID: 38534338 DOI: 10.3390/cells13060494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 03/28/2024] Open
Abstract
Stem cell maintenance and differentiation can be regulated via the differential activity of transcription factors within stem cells and their progeny. For these factors to be active, they need to be transported from their site of synthesis in the cytoplasm into the nucleus. A tissue-specific requirement for factors involved in nuclear importation is a potential mechanism to regulate stem cell differentiation. We have undertaken a characterization of male sterile importin alpha 1 (Dα1) null alleles in Drosophila and found that Dα1 is required for maintaining germline stem cells (GSCs) in the testis niche. The loss of GSCs can be rescued by ectopic expression of Dα1 within the germline but the animals are still infertile, indicating a second role for Dα1 in spermatogenesis. Expression of a Dα1 dominant negative transgene in GSCs confirmed a functional requirement for Dα1 in GSC maintenance but expression of the transgene in differentiating spermatogonia did not exhibit a phenotype indicating a specific role for Dα1 within GSCs. Our data indicate that Dα1 is utilized as a regulatory protein within GSCs to facilitate nuclear importation of proteins that maintain the stem cell pool.
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Affiliation(s)
- James Heaney
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jiamin Zhao
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Franca Casagranda
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Kate L Loveland
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia
- Department of Molecular and Translational Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Nicole A Siddall
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Gary R Hime
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC 3010, Australia
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2
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Wharton TH, Marhabaie M, Wharton RP. Significant roles in RNA-binding for the amino-terminal domains of Drosophila Pumilio and Nanos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563753. [PMID: 37961211 PMCID: PMC10634786 DOI: 10.1101/2023.10.24.563753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The Drosophila Pumilio (Pum) and Nanos (Nos) RNA-binding proteins govern abdominal segmentation in the early embryo, as well as a variety of other events during development. They bind together to a compound Nanos Response Element (NRE) present in thousands of maternal mRNAs in the ovary and embryo, including hunchback ( hb ) mRNA, thereby regulating poly-adenylation, translation, and stability. Many studies support a model in which mRNA recognition and effector recruitment are achieved by distinct regions of each protein. The well-ordered Pum and Nos RNA-binding domains (RBDs) are sufficient to specifically recognize NREs; the relatively larger low-complexity N-terminal domains (NTDs) of each protein have been thought to act by recruiting mRNA regulators. Here we use yeast interaction assays to show that the NTDs also play a significant role in recognition of the NRE, acting via two mechanisms. First, the Pum and Nos NTDs interact in trans to promote assembly of the Pum/Nos/NRE ternary complex. Second, the Pum NTD acts via an unknown mechanism in cis, modifying base recognition by its RBD. These activities of the Pum NTD are important for its regulation of maternal hb mRNA in vivo.
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3
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Marhabaie M, Wharton TH, Kim SY, Wharton RP. Widespread regulation of the maternal transcriptome by Nanos in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.555109. [PMID: 37693559 PMCID: PMC10491125 DOI: 10.1101/2023.08.28.555109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The translational repressor Nanos (Nos) regulates a single target, maternal hunchback (hb) mRNA, to govern abdominal segmentation in the early Drosophila embryo. Nos is recruited specifically to sites in the 3'-UTR of hb mRNA in collaboration with the sequence-specific RNA-binding protein Pumilio (Pum); on its own, Nos has no binding specificity. Nos is expressed at other stages of development, but very few mRNA targets that might mediate its action at these stages have been described. Nor has it been clear whether Nos is targeted to other mRNAs in concert with Pum or via other mechanisms. In this report, we identify mRNAs targeted by Nos via two approaches. In the first method, we identify mRNAs depleted upon expression of a chimera bearing Nos fused to the nonsense mediated decay (NMD) factor Upf1. We find that, in addition to hb, Upf1-Nos depletes ~2600 mRNAs from the maternal transcriptome in early embryos. Virtually all of these appear to be targeted in a canonical, hb-like manner in concert with Pum. In a second, more conventional approach, we identify mRNAs that are stabilized during the maternal zygotic transition (MZT) in embryos from nos- females. Most (86%) of the 1185 mRNAs regulated by Nos are also targeted by Upf1-Nos, validating use of the chimera. Approximately 60% of mRNAs targeted by Upf1-Nos are not stabilized in the absence of Nos. However, Upf1-Nos mRNA targets are hypo-adenylated and inefficiently translated at the ovary-embryo transition, whether or not they suffer Nos-dependent degradation in the embryo. We suggest that the late ovarian burst of Nos represses a large fraction of the maternal transcriptome, priming it for later degradation by other factors during the MZT in the embryo.
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4
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Hakes AC, Gavis ER. Plasticity of Drosophila germ granules during germ cell development. PLoS Biol 2023; 21:e3002069. [PMID: 37053289 PMCID: PMC10128949 DOI: 10.1371/journal.pbio.3002069] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/25/2023] [Accepted: 03/07/2023] [Indexed: 04/15/2023] Open
Abstract
Compartmentalization of RNAs and proteins into membraneless structures called granules is a ubiquitous mechanism for organizing and regulating cohorts of RNAs. Germ granules are ribonucleoprotein (RNP) assemblies required for germline development across the animal kingdom, but their regulatory roles in germ cells are not fully understood. We show that after germ cell specification, Drosophila germ granules enlarge through fusion and this growth is accompanied by a shift in function. Whereas germ granules initially protect their constituent mRNAs from degradation, they subsequently target a subset of these mRNAs for degradation while maintaining protection of others. This functional shift occurs through the recruitment of decapping and degradation factors to the germ granules, which is promoted by decapping activators and renders these structures P body-like. Disrupting either the mRNA protection or degradation function results in germ cell migration defects. Our findings reveal plasticity in germ granule function that allows them to be repurposed at different stages of development to ensure population of the gonad by germ cells. Additionally, these results reveal an unexpected level of functional complexity whereby constituent RNAs within the same granule type can be differentially regulated.
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Affiliation(s)
- Anna C Hakes
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Elizabeth R Gavis
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
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5
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Wu JW, Wang CW, Chen RY, Hung LY, Tsai YC, Chan YT, Chang YC, Jang ACC. Spatiotemporal gating of Stat nuclear influx by Drosophila Npas4 in collective cell migration. SCIENCE ADVANCES 2022; 8:eabm2411. [PMID: 35867785 PMCID: PMC9307255 DOI: 10.1126/sciadv.abm2411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Collective migration is important to embryonic development and cancer metastasis, but migratory and nonmigratory cell fate discrimination by differential activity of signal pathways remains elusive. In Drosophila oogenesis, Jak/Stat signaling patterns the epithelial cell fates in early egg chambers but later renders motility to clustered border cells. How Jak/Stat signal spatiotemporally switches static epithelia to motile cells is largely unknown. We report that a nuclear protein, Dysfusion, resides on the inner nuclear membrane and interacts with importin α/β and Nup153 to modulate Jak/Stat signal by attenuating Stat nuclear import. Dysfusion is ubiquitously expressed in oogenesis but specifically down-regulated in border cells when migrating. Increase of nuclear Stat by Dysfusion down-regulation triggers invasive cell behavior and maintains persistent motility. Mammalian homolog of Dysfusion (NPAS4) also negatively regulates the nuclear accumulation of STAT3 and cancer cell migration. Thus, our finding demonstrates that Dysfusion-dependent gating mechanism is conserved and may serve as a therapeutic target for Stat-mediated cancer metastasis.
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Affiliation(s)
- Jhen-Wei Wu
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, 1 University Rd, Tainan City 70101, Taiwan
| | - Chueh-Wen Wang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, 1 University Rd, Tainan City 70101, Taiwan
| | - Ruo-Yu Chen
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, 1 University Rd, Tainan City 70101, Taiwan
| | - Liang-Yi Hung
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, 1 University Rd, Tainan City 70101, Taiwan
| | - Yu-Chen Tsai
- Department of Life Science and Life Science Center, Tunghai University, No.1727, Sec.4, Taiwan Boulevard, Taichung City 407224, Taiwan
| | - Yu-Ting Chan
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, 1 University Rd, Tainan City 70101, Taiwan
| | - Yu-Chiuan Chang
- Institute of Biomedical Sciences, National Sun Yat-sen University, 70 Lien-Hai Rd, Kaohsiung 80424, Taiwan
| | - Anna C.-C. Jang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, 1 University Rd, Tainan City 70101, Taiwan
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6
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Hirano T, Wright D, Suzuki A, Saga Y. A cooperative mechanism of target RNA selection via germ-cell-specific RNA-binding proteins NANOS2 and DND1. Cell Rep 2022; 39:110894. [PMID: 35705038 DOI: 10.1016/j.celrep.2022.110894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 12/09/2021] [Accepted: 05/06/2022] [Indexed: 11/03/2022] Open
Abstract
The germ-cell-specific RNA-binding protein (RBP) NANOS2 plays a pivotal role in male gonocyte differentiation and spermatogonial stem cell maintenance. Although NANOS2 interacts with the CNOT deadenylation complex and Dead end 1 (DND1) to repress target RNAs, the molecular mechanisms underlying target mRNA selection remain unclear because of the limited cell resource in vivo. Here, we demonstrate that exogenous NANOS2-DND1 suppresses target mRNAs in somatic cells. Using this somatic cell system, we find that NANOS2 interacts with RNA-bound DND1 and recruits the CNOT complex to the mRNAs. However, a fusion construct composed of the CNOT1-binding site of NANOS2 (NIM) and DND1 fails to repress the target gene expression. Therefore, NANOS2 is required not only for recruitment of the CNOT complex but also for selecting the target mRNA with DND1. This study reveals that NANOS2 functions as a second-layer RBP for the target recognition and functional adaptation of DND1.
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Affiliation(s)
- Takamasa Hirano
- Mammalian Development Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Mishima, Shizuoka 411-8582, Japan
| | - Danelle Wright
- Mammalian Development Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Mishima, Shizuoka 411-8582, Japan; Department of Genetics, SOKENDAI, 1111 Mishima, Shizuoka 411-8582, Japan
| | - Atsushi Suzuki
- Division of Materials Science and Chemical Engineering, Graduate School of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 Japan
| | - Yumiko Saga
- Mammalian Development Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Mishima, Shizuoka 411-8582, Japan; Department of Genetics, SOKENDAI, 1111 Mishima, Shizuoka 411-8582, Japan; Division for Development of Genetic-Engineered Mouse Resource, Genetic Resource Center, National Institute of Genetics, 1111 Mishima, Shizuoka 411-8582, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
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7
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Asaoka M, Sakamaki Y, Fukumoto T, Nishimura K, Tomaru M, Takano-Shimizu T, Tanaka D, Kobayashi S. Offspring production from cryopreserved primordial germ cells in Drosophila. Commun Biol 2021; 4:1159. [PMID: 34621004 PMCID: PMC8497528 DOI: 10.1038/s42003-021-02692-z] [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: 12/24/2020] [Accepted: 09/17/2021] [Indexed: 11/29/2022] Open
Abstract
There is an urgent need to cryopreserve Drosophila stocks that have been maintained as living cultures for a long time. Long-term culture increases the risk of accidental loss and of unwanted genetic alteration. Here, we report that cryopreserved primordial germ cells (PGCs) can produce F1 progeny when transplanted into hosts. The cryopreserved donor PGCs could form germline stem cells in host gonads and contributed to continuous offspring production. Furthermore, the ability to produce offspring did not appear to vary with either differences between donor strains or cryopreservation duration. Therefore, we propose that our cryopreservation method is feasible for long-term storage of various Drosophila strains. These results underscore the potential usefulness of our cryopreservation method for backing up living stocks to avoid either accidental loss or genetic alteration. Asaoka, Sakamaki, Fukumoto et al. present a more viable method of long-term storage of Drosophila fly strains by cryopreservation of primordial germ cells (PGCs) without any drop in viability. The authors show that PGCs from stage 5 embryos can be transplanted into embryos and properly developed into germline stem cells to produce offspring of both sexes after being revived from storage in liquid nitrogen.
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Affiliation(s)
- Miho Asaoka
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Yurina Sakamaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
| | - Tatsuya Fukumoto
- Research Center of Genetic Resources, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, 305-8602, Japan
| | - Kaori Nishimura
- Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Kyoto, 616-8354, Japan
| | - Masatoshi Tomaru
- Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Kyoto, 616-8354, Japan
| | - Toshiyuki Takano-Shimizu
- Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Kyoto, 616-8354, Japan.
| | - Daisuke Tanaka
- Research Center of Genetic Resources, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, 305-8602, Japan.
| | - Satoru Kobayashi
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan. .,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
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8
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Li YR, Lai HW, Huang HH, Chen HC, Fugmann SD, Yang SY. Trajectory mapping of the early Drosophila germline reveals controls of zygotic activation and sex differentiation. Genome Res 2021; 31:1011-1023. [PMID: 33858841 PMCID: PMC8168578 DOI: 10.1101/gr.271148.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 04/07/2021] [Indexed: 01/29/2023]
Abstract
Germ cells in Drosophila melanogaster are specified maternally shortly after fertilization and are transcriptionally quiescent until their zygotic genome is activated to sustain further development. To understand the molecular basis of this process, we analyzed the progressing transcriptomes of early male and female germ cells at the single-cell level between germline specification and coalescence with somatic gonadal cells. Our data comprehensively cover zygotic activation in the germline genome, and analyses on genes that exhibit germline-restricted expression reveal that polymerase pausing and differential RNA stability are important mechanisms that establish gene expression differences between the germline and soma. In addition, we observe an immediate bifurcation between the male and female germ cells as zygotic transcription begins. The main difference between the two sexes is an elevation in X Chromosome expression in females relative to males, signifying incomplete dosage compensation, with a few select genes exhibiting even higher expression increases. These indicate that the male program is the default mode in the germline that is driven to female development with a second X Chromosome.
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Affiliation(s)
- Yi-Ru Li
- Department and College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan
| | - Hsiao Wen Lai
- Department and College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan
| | - Hsiao Han Huang
- Department and College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan
| | - Hsing-Chun Chen
- Department and College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan
| | - Sebastian D Fugmann
- Department and College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan.,Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan.,Department of Nephrology, Linkou Chang Gung Memorial Hospital, Kweishan, Taoyuan 333 Taiwan
| | - Shu Yuan Yang
- Department and College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan.,Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan.,Department of Gynecology, Linkou Chang Gung Memorial Hospital, Kweishan, Taoyuan 333 Taiwan
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9
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Mehmood R, Jibiki K, Shibazaki N, Yasuhara N. Molecular profiling of nucleocytoplasmic transport factor genes in breast cancer. Heliyon 2021; 7:e06039. [PMID: 33553736 PMCID: PMC7851789 DOI: 10.1016/j.heliyon.2021.e06039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 12/14/2020] [Accepted: 01/14/2021] [Indexed: 11/24/2022] Open
Abstract
Transport of functional molecules across the nuclear membrane of a eukaryotic cell is regulated by a dedicated set of transporter proteins that carry molecules into the nucleus or out of the nucleus to the cytoplasm for homeostasis of the cell. One of the categories of cargo molecules these transporters carry are the molecules for cell cycle regulation. Therefore, their role is critical in terms of cancer development. Any misregulation of the transport factors would means aberrant abundance of cell cycle regulators and might have consequences in cell cycle progression. While earlier studies have focussed on individual transport related molecules, a collective overview of how these molecules may be dysregulated in breast cancer is lacking. Using genomic and transcriptomic datasets from TCGA (The Cancer Genome Atlas) and microarray platforms, we carried out bioinformatic analysis and provide a genetic and molecular profile of all the molecules directly related to nucleocytoplasmic shuttling of proteins and RNAs. Interestingly, we identified that many of these molecules are either mutated or have dysregulated expression in breast cancer. Strikingly, some of the molecules, namely, KPNA2, KPNA3, KPNA5, IPO8, TNPO1, XPOT, XPO7 and CSE1L were correlated with poor patient survival. This study provides a comprehensive genetic and molecular landscape of nucleocytoplasmic factors in breast cancer and points to the important roles of various nucleocytoplasmic factors in cancer progression. This data might have implications in prognosis and therapeutic targeting in breast cancer.
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Affiliation(s)
- Rashid Mehmood
- Department of Life Sciences, College of Science and General Studies, Alfaisal University, Riyadh, Kingdom of Saudi Arabia
| | - Kazuya Jibiki
- Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
| | - Noriko Shibazaki
- Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
| | - Noriko Yasuhara
- Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
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10
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Colonnetta MM, Lym LR, Wilkins L, Kappes G, Castro EA, Ryder PV, Schedl P, Lerit DA, Deshpande G. Antagonism between germ cell-less and Torso receptor regulates transcriptional quiescence underlying germline/soma distinction. eLife 2021; 10:54346. [PMID: 33459591 PMCID: PMC7843132 DOI: 10.7554/elife.54346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/15/2021] [Indexed: 11/13/2022] Open
Abstract
Transcriptional quiescence, an evolutionarily conserved trait, distinguishes the embryonic primordial germ cells (PGCs) from their somatic neighbors. In Drosophila melanogaster, PGCs from embryos maternally compromised for germ cell-less (gcl) misexpress somatic genes, possibly resulting in PGC loss. Recent studies documented a requirement for Gcl during proteolytic degradation of the terminal patterning determinant, Torso receptor. Here we demonstrate that the somatic determinant of female fate, Sex-lethal (Sxl), is a biologically relevant transcriptional target of Gcl. Underscoring the significance of transcriptional silencing mediated by Gcl, ectopic expression of a degradation-resistant form of Torso (torsoDeg) can activate Sxl transcription in PGCs, whereas simultaneous loss of torso-like (tsl) reinstates the quiescent status of gcl PGCs. Intriguingly, like gcl mutants, embryos derived from mothers expressing torsoDeg in the germline display aberrant spreading of pole plasm RNAs, suggesting that mutual antagonism between Gcl and Torso ensures the controlled release of germ-plasm underlying the germline/soma distinction.
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Affiliation(s)
- Megan M Colonnetta
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Lauren R Lym
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Lillian Wilkins
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Gretchen Kappes
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Elias A Castro
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Pearl V Ryder
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Dorothy A Lerit
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Girish Deshpande
- Department of Molecular Biology, Princeton University, Princeton, United States
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11
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Serway CN, Dunkelberger BS, Del Padre D, Nolan NWC, Georges S, Freer S, Andres AJ, de Belle JS. Importin-α2 mediates brain development, learning and memory consolidation in Drosophila. J Neurogenet 2020; 34:69-82. [PMID: 31965871 DOI: 10.1080/01677063.2019.1709184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Neuronal development and memory consolidation are conserved processes that rely on nuclear-cytoplasmic transport of signaling molecules to regulate gene activity and initiate cascades of downstream cellular events. Surprisingly, few reports address and validate this widely accepted perspective. Here we show that Importin-α2 (Imp-α2), a soluble nuclear transporter that shuttles cargoes between the cytoplasm and nucleus, is vital for brain development, learning and persistent memory in Drosophila melanogaster. Mutations in importin-α2 (imp-α2, known as Pendulin or Pen and homologous with human KPNA2) are alleles of mushroom body miniature B (mbmB), a gene known to regulate aspects of brain development and influence adult behavior in flies. Mushroom bodies (MBs), paired associative centers in the brain, are smaller than normal due to defective proliferation of specific intrinsic Kenyon cell (KC) neurons in mbmB mutants. Extant KCs projecting to the MB β-lobe terminate abnormally on the contralateral side of the brain. mbmB adults have impaired olfactory learning but normal memory decay in most respects, except that protein synthesis-dependent long-term memory (LTM) is abolished. This observation supports an alternative mechanism of persistent memory in which mutually exclusive protein-synthesis-dependent and -independent forms rely on opposing cellular mechanisms or circuits. We propose a testable model of Imp-α2 and nuclear transport roles in brain development and conditioned behavior. Based on our molecular characterization, we suggest that mbmB is hereafter referred to as imp-α2mbmB.
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Affiliation(s)
- Christine N Serway
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, USA
| | - Brian S Dunkelberger
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Las Vegas High School, Las Vegas, NV, USA
| | - Denise Del Padre
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA
| | - Nicole W C Nolan
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Methodist Estabrook Cancer Center, Omaha, NE, USA
| | - Stephanie Georges
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Stephanie Freer
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Research Square Inc, Nashville, TN, USA
| | - Andrew J Andres
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA
| | - J Steven de Belle
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Department of Psychological Sciences, University of San Diego, San Diego, CA, USA
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