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Banik J, Moreira ARS, Lim J, Tomlinson S, Hardy LL, Lagasse A, Haney A, Crimmins MR, Boehm U, Odle AK, MacNicol MC, Childs GV, MacNicol AM. The Musashi RNA binding proteins direct the translational activation of key pituitary mRNAs. Sci Rep 2024; 14:5918. [PMID: 38467682 PMCID: PMC10928108 DOI: 10.1038/s41598-024-56002-8] [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: 09/22/2023] [Accepted: 02/29/2024] [Indexed: 03/13/2024] Open
Abstract
The pituitary functions as a master endocrine gland that secretes hormones critical for regulation of a wide variety of physiological processes including reproduction, growth, metabolism and stress responses. The distinct hormone-producing cell lineages within the pituitary display remarkable levels of cell plasticity that allow remodeling of the relative proportions of each hormone-producing cell population to meet organismal demands. The molecular mechanisms governing pituitary cell plasticity have not been fully elucidated. Our recent studies have implicated a role for the Musashi family of sequence-specific mRNA binding proteins in the control of pituitary hormone production, pituitary responses to hypothalamic stimulation and modulation of pituitary transcription factor expression in response to leptin signaling. To date, these actions of Musashi in the pituitary appear to be mediated through translational repression of the target mRNAs. Here, we report Musashi1 directs the translational activation, rather than repression, of the Prop1, Gata2 and Nr5a1 mRNAs which encode key pituitary lineage specification factors. We observe that Musashi1 further directs the translational activation of the mRNA encoding the glycolipid Neuronatin (Nnat) as determined both in mRNA reporter assays as well as in vivo. Our findings suggest a complex bifunctional role for Musashi1 in the control of pituitary cell function.
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Affiliation(s)
- Jewel Banik
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Ana Rita Silva Moreira
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Juchan Lim
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Sophia Tomlinson
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Linda L Hardy
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Alex Lagasse
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Anessa Haney
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Meghan R Crimmins
- Arkansas Children's Nutrition Center, Arkansas Children's Hospital, Little Rock, AR, USA
| | - Ulrich Boehm
- Department of Experimental Pharmacology, Center for Molecular Signaling, Saarland University School of Medicine, Homburg, Germany
| | - Angela K Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Gwen V Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W Markham, Slot 814, Little Rock, AR, 72205, USA.
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2
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Moreira ARS, Lim J, Urbaniak A, Banik J, Bronson K, Lagasse A, Hardy L, Haney A, Allensworth M, Miles TK, Gies A, Byrum SD, Wilczynska A, Boehm U, Kharas M, Lengner C, MacNicol MC, Childs GV, MacNicol AM, Odle AK. Musashi Exerts Control of Gonadotrope Target mRNA Translation During the Mouse Estrous Cycle. Endocrinology 2023; 164:bqad113. [PMID: 37477898 PMCID: PMC10402870 DOI: 10.1210/endocr/bqad113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/30/2023] [Accepted: 07/20/2023] [Indexed: 07/22/2023]
Abstract
The anterior pituitary controls key biological processes, including growth, metabolism, reproduction, and stress responses through distinct cell types that each secrete specific hormones. The anterior pituitary cells show a remarkable level of cell type plasticity that mediates the shifts in hormone-producing cell populations that are required to meet organismal needs. The molecular mechanisms underlying pituitary cell plasticity are not well understood. Recent work has implicated the pituitary stem cell populations and specifically, the mRNA binding proteins of the Musashi family in control of pituitary cell type identity. In this study we have identified the target mRNAs that mediate Musashi function in the adult mouse pituitary and demonstrate the requirement for Musashi function in vivo. Using Musashi RNA immunoprecipitation, we identify a cohort of 1184 mRNAs that show specific Musashi binding. Identified Musashi targets include the Gnrhr mRNA, which encodes the gonadotropin-releasing hormone receptor (GnRHR), and the Fshb mRNA, encoding follicle-stimulating hormone (FSH). Reporter assays reveal that Musashi functions to exert repression of translation of the Fshb mRNA, in addition to the previously observed repression of the Gnrhr mRNA. Importantly, mice engineered to lack Musashi in gonadotropes demonstrate a failure to repress translation of the endogenous Gnrhr and Fshb mRNAs during the estrous cycle and display a significant heterogeneity in litter sizes. The range of identified target mRNAs suggests that, in addition to these key gonadotrope proteins, Musashi may exert broad regulatory control over the pituitary proteome in a cell type-specific manner.
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Affiliation(s)
- Ana Rita Silva Moreira
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Juchan Lim
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Alicja Urbaniak
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Jewel Banik
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Katherine Bronson
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Alex Lagasse
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Linda Hardy
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Anessa Haney
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Melody Allensworth
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Tiffany K Miles
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Allen Gies
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
- Arkansas Children's Research Institute, Arkansas Children's Hospital, Little Rock, AR 72202, USA
| | - Ania Wilczynska
- Bit.bio, The Dorothy Hodgkin Building, Babraham Research Campus, Cambridge CB22 3FH, UK
| | - Ulrich Boehm
- Department of Experimental Pharmacology, Center for Molecular Signaling, Saarland University School of Medicine, Homburg 66421, Germany
| | - Michael Kharas
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Christopher Lengner
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19146, USA
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Gwen V Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Angela K Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Jiang Y, Adhikari D, Li C, Zhou X. Spatiotemporal regulation of maternal mRNAs during vertebrate oocyte meiotic maturation. Biol Rev Camb Philos Soc 2023; 98:900-930. [PMID: 36718948 DOI: 10.1111/brv.12937] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 02/01/2023]
Abstract
Vertebrate oocytes face a particular challenge concerning the regulation of gene expression during meiotic maturation. Global transcription becomes quiescent in fully grown oocytes, remains halted throughout maturation and fertilization, and only resumes upon embryonic genome activation. Hence, the oocyte meiotic maturation process is largely regulated by protein synthesis from pre-existing maternal messenger RNAs (mRNAs) that are transcribed and stored during oocyte growth. Rapidly developing genome-wide techniques have greatly expanded our insights into the global translation changes and possible regulatory mechanisms during oocyte maturation. The storage, translation, and processing of maternal mRNAs are thought to be regulated by factors interacting with elements in the mRNA molecules. Additionally, posttranscriptional modifications of mRNAs, such as methylation and uridylation, have recently been demonstrated to play crucial roles in maternal mRNA destabilization. However, a comprehensive understanding of the machineries that regulate maternal mRNA fate during oocyte maturation is still lacking. In particular, how the transcripts of important cell cycle components are stabilized, recruited at the appropriate time for translation, and eliminated to modulate oocyte meiotic progression remains unclear. A better understanding of these mechanisms will provide invaluable insights for the preconditions of developmental competence acquisition, with important implications for the treatment of infertility. This review discusses how the storage, localization, translation, and processing of oocyte mRNAs are regulated, and how these contribute to oocyte maturation progression.
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Affiliation(s)
- Yanwen Jiang
- College of Animal Science, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Deepak Adhikari
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, 19 Innovation Walk, Melbourne, VIC, 3800, Australia
| | - Chunjin Li
- College of Animal Science, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Xu Zhou
- College of Animal Science, Jilin University, 5333 Xian Road, Changchun, 130062, China
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Mastrandreas P, Boglari C, Arnold A, Peter F, de Quervain DJF, Papassotiropoulos A, Stetak A. Phosphorylation of MSI-1 is implicated in the regulation of associative memory in Caenorhabditis elegans. PLoS Genet 2022; 18:e1010420. [PMID: 36223338 PMCID: PMC9555661 DOI: 10.1371/journal.pgen.1010420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/09/2022] [Indexed: 11/07/2022] Open
Abstract
The Musashi family of RNA-binding proteins controls several biological processes including stem cell maintenance, cell division and neural function. Previously, we demonstrated that the C. elegans Musashi ortholog, msi-1, regulates forgetting via translational repression of the Arp2/3 actin-branching complex. However, the mechanisms controlling MSI-1 activity during the regulation of forgetting are currently unknown. Here we investigated the effects of protein phosphorylation on MSI-1 activity. We showed that MSI-1 function is likely controlled by alterations of its activity rather than its expression levels. Furthermore, we found that MSI-1 is phosphorylated and using mass spectrometry we identified MSI-1 phosphorylation at three residues (T18, S19 and S34). CRISPR-based manipulations of MSI-1 phosphorylation sites revealed that phosphorylation is necessary for MSI-1 function in both short- and long-term aversive olfactory associative memory. Thus, our study provides insight into the mechanisms regulating memory-related MSI-1 activity and may facilitate the development of novel therapeutic approaches. Understanding neural circuits and molecular mechanisms underlying learning and memory are the major challenges of neuroscience. It is a generally accepted model that a learning event causes modification of synapses; strengthening some within a circuit and weakening others (termed “synaptic plasticity”). A plastic nervous system requires not only the ability to acquire and store but also to forget new inputs. While learning and memory is widely investigated, clear-cut evidence for mechanisms involved in forgetting is still sparse. Previously, we demonstrated the role of the protein Musashi (MSI-1) in the active regulation of forgetting in the nematode C. elegans. Here we investigated the role of protein modification (phosphorylation) as a possible regulatory mechanism of the MSI-1 protein activity. We found that MSI-1 protein is modified at different positions and all of these modifications at the protein level contribute to the correct activity of the protein leading to active forgetting of short and long-term memories.
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Affiliation(s)
- Pavlina Mastrandreas
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Csaba Boglari
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Andreas Arnold
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Fabian Peter
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Dominique J.-F. de Quervain
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Cognitive Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- University Psychiatric Clinics, University of Basel, Basel, Switzerland
| | - Andreas Papassotiropoulos
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
- University Psychiatric Clinics, University of Basel, Basel, Switzerland
| | - Attila Stetak
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
- University Psychiatric Clinics, University of Basel, Basel, Switzerland
- * E-mail:
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5
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Landínez-Macías M, Urwyler O. The Fine Art of Writing a Message: RNA Metabolism in the Shaping and Remodeling of the Nervous System. Front Mol Neurosci 2021; 14:755686. [PMID: 34916907 PMCID: PMC8670310 DOI: 10.3389/fnmol.2021.755686] [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: 08/09/2021] [Accepted: 10/18/2021] [Indexed: 01/25/2023] Open
Abstract
Neuronal morphogenesis, integration into circuits, and remodeling of synaptic connections occur in temporally and spatially defined steps. Accordingly, the expression of proteins and specific protein isoforms that contribute to these processes must be controlled quantitatively in time and space. A wide variety of post-transcriptional regulatory mechanisms, which act on pre-mRNA and mRNA molecules contribute to this control. They are thereby critically involved in physiological and pathophysiological nervous system development, function, and maintenance. Here, we review recent findings on how mRNA metabolism contributes to neuronal development, from neural stem cell maintenance to synapse specification, with a particular focus on axon growth, guidance, branching, and synapse formation. We emphasize the role of RNA-binding proteins, and highlight their emerging roles in the poorly understood molecular processes of RNA editing, alternative polyadenylation, and temporal control of splicing, while also discussing alternative splicing, RNA localization, and local translation. We illustrate with the example of the evolutionary conserved Musashi protein family how individual RNA-binding proteins are, on the one hand, acting in different processes of RNA metabolism, and, on the other hand, impacting multiple steps in neuronal development and circuit formation. Finally, we provide links to diseases that have been associated with the malfunction of RNA-binding proteins and disrupted post-transcriptional regulation.
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Affiliation(s)
- María Landínez-Macías
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Molecular Life Sciences Program, Life Science Zurich Graduate School, University of Zurich and Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | - Olivier Urwyler
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Molecular Life Sciences Program, Life Science Zurich Graduate School, University of Zurich and Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland.,Neuroscience Center Zurich (ZNZ), University of Zurich, Zurich, Switzerland
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6
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The RNA-binding protein Musashi controls axon compartment-specific synaptic connectivity through ptp69D mRNA poly(A)-tailing. Cell Rep 2021; 36:109713. [PMID: 34525368 DOI: 10.1016/j.celrep.2021.109713] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/24/2020] [Accepted: 08/24/2021] [Indexed: 10/20/2022] Open
Abstract
Synaptic targeting with subcellular specificity is essential for neural circuit assembly. Developing neurons use mechanisms to curb promiscuous synaptic connections and to direct synapse formation to defined subcellular compartments. How this selectivity is achieved molecularly remains enigmatic. Here, we discover a link between mRNA poly(A)-tailing and axon collateral branch-specific synaptic connectivity within the CNS. We reveal that the RNA-binding protein Musashi binds to the mRNA encoding the receptor protein tyrosine phosphatase Ptp69D, thereby increasing poly(A) tail length and Ptp69D protein levels. This regulation specifically promotes synaptic connectivity in one axon collateral characterized by a high degree of arborization and strong synaptogenic potential. In a different compartment of the same axon, Musashi prevents ectopic synaptogenesis, revealing antagonistic, compartment-specific functions. Moreover, Musashi-dependent Ptp69D regulation controls synaptic connectivity in the olfactory circuit. Thus, Musashi differentially shapes synaptic connectivity at the level of individual subcellular compartments and within different developmental and neuron type-specific contexts.
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Allensworth-James ML, Odle AK, Lim J, LaGasse AN, Miles TK, Hardy LL, Haney AC, MacNicol MC, MacNicol AM, Childs GV. Metabolic signalling to somatotrophs: Transcriptional and post-transcriptional mediators. J Neuroendocrinol 2020; 32:e12883. [PMID: 32657474 PMCID: PMC8086172 DOI: 10.1111/jne.12883] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/17/2020] [Accepted: 06/10/2020] [Indexed: 12/19/2022]
Abstract
In normal individuals, pituitary somatotrophs optimise body composition by responding to metabolic signals from leptin. To identify mechanisms behind the regulation of somatotrophs by leptin, we used Cre-LoxP technology to delete leptin receptors (LEPR) selectively in somatotrophs and developed populations purified by fluorescence-activated cell sorting (FACS) that contained 99% somatotrophs. FACS-purified, Lepr-null somatotrophs showed reduced levels of growth hormone (GH), growth hormone-releasing hormone receptor (GHRHR), and Pou1f1 proteins and Gh (females) and Ghrhr (both sexes) mRNAs. Pure somatotrophs also expressed thyroid-stimulating hormone (TSH) and prolactin (PRL), both of which were reduced in pure somatotrophs lacking LEPR. This introduced five gene products that were targets of leptin. In the present study, we tested the hypothesis that leptin is both a transcriptional and a post-transcriptional regulator of these gene products. Our tests showed that Pou1f1 and/or the Janus kinase/signal transducer and activator of transcription 3 transcriptional regulatory pathways are implicated in the leptin regulation of Gh or Ghrhr mRNAs. We then focused on potential actions by candidate microRNAs (miRNAs) with consensus binding sites on the 3' UTR of Gh or Ghrhr mRNAs. Somatotroph Lepr-null deletion mutants expressed elevated levels of miRNAs including miR1197-3p (in females), miR103-3p and miR590-3p (both sexes), which bind Gh mRNA, or miRNA-325-3p (elevated in both sexes), which binds Ghrhr mRNA. This elevation indicates repression of translation in the absence of LEPR. In addition, after detecting binding sites for Musashi on Tshb and Prl 3' UTR, we determined that Musashi1 repressed translation of both mRNAs in in vitro fluc assays and that Prl mRNA was enriched in Musashi immunoprecipitation assays. Finally, we tested ghrelin actions to determine whether its nitric oxide-mediated signalling pathways would restore somatotroph functions in deletion mutants. Ghrelin did not restore either GHRH binding or GH secretion in vitro. These studies show an unexpectedly broad role for leptin with respect to maintaining somatotroph functions, including the regulation of PRL and TSH in subsets of somatotrophs that may be progenitor cells.
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Affiliation(s)
- Melody L Allensworth-James
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Angela K Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Juchan Lim
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Alex N LaGasse
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Tiffany K Miles
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Linda L Hardy
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Anessa C Haney
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gwen V Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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Meneau F, Dupré A, Jessus C, Daldello EM. Translational Control of Xenopus Oocyte Meiosis: Toward the Genomic Era. Cells 2020; 9:E1502. [PMID: 32575604 PMCID: PMC7348711 DOI: 10.3390/cells9061502] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/28/2020] [Accepted: 06/17/2020] [Indexed: 12/18/2022] Open
Abstract
The study of oocytes has made enormous contributions to the understanding of the G2/M transition. The complementarity of investigations carried out on various model organisms has led to the identification of the M-phase promoting factor (MPF) and to unravel the basis of cell cycle regulation. Thanks to the power of biochemical approaches offered by frog oocytes, this model has allowed to identify the core signaling components involved in the regulation of M-phase. A central emerging layer of regulation of cell division regards protein translation. Oocytes are a unique model to tackle this question as they accumulate large quantities of dormant mRNAs to be used during meiosis resumption and progression, as well as the cell divisions during early embryogenesis. Since these events occur in the absence of transcription, they require cascades of successive unmasking, translation, and discarding of these mRNAs, implying a fine regulation of the timing of specific translation. In the last years, the Xenopus genome has been sequenced and annotated, enabling the development of omics techniques in this model and starting its transition into the genomic era. This review has critically described how the different phases of meiosis are orchestrated by changes in gene expression. The physiological states of the oocyte have been described together with the molecular mechanisms that control the critical transitions during meiosis progression, highlighting the connection between translation control and meiosis dynamics.
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Affiliation(s)
| | | | | | - Enrico Maria Daldello
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement—Institut de Biologie Paris Seine, LBD—IBPS, F-75005 Paris, France; (F.M.); (A.D.); (C.J.)
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Cragle CE, MacNicol MC, Byrum SD, Hardy LL, Mackintosh SG, Richardson WA, Gray NK, Childs GV, Tackett AJ, MacNicol AM. Musashi interaction with poly(A)-binding protein is required for activation of target mRNA translation. J Biol Chem 2019; 294:10969-10986. [PMID: 31152063 PMCID: PMC6635449 DOI: 10.1074/jbc.ra119.007220] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/09/2019] [Indexed: 12/21/2022] Open
Abstract
The Musashi family of mRNA translational regulators controls both physiological and pathological stem cell self-renewal primarily by repressing target mRNAs that promote differentiation. In response to differentiation cues, Musashi can switch from a repressor to an activator of target mRNA translation. However, the molecular events that distinguish Musashi-mediated translational activation from repression are not understood. We have previously reported that Musashi function is required for the maturation of Xenopus oocytes and specifically for translational activation of specific dormant maternal mRNAs. Here, we employed MS to identify cellular factors necessary for Musashi-dependent mRNA translational activation. We report that Musashi1 needs to associate with the embryonic poly(A)-binding protein (ePABP) or the canonical somatic cell poly(A)-binding protein PABPC1 for activation of Musashi target mRNA translation. Co-immunoprecipitation studies demonstrated an increased Musashi1 interaction with ePABP during oocyte maturation. Attenuation of endogenous ePABP activity severely compromised Musashi function, preventing downstream signaling and blocking oocyte maturation. Ectopic expression of either ePABP or PABPC1 restored Musashi-dependent mRNA translational activation and maturation of ePABP-attenuated oocytes. Consistent with these Xenopus findings, PABPC1 remained associated with Musashi under conditions of Musashi target mRNA de-repression and translation during mammalian stem cell differentiation. Because association of Musashi1 with poly(A)-binding proteins has previously been implicated only in repression of Musashi target mRNAs, our findings reveal novel context-dependent roles for the interaction of Musashi with poly(A)-binding protein family members in response to extracellular cues that control cell fate.
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Affiliation(s)
- Chad E Cragle
- Department of Neurobiology and Developmental Sciences
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences,; Center for Translational Neuroscience
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology,; Arkansas Children's Research Institute
| | - Linda L Hardy
- Department of Neurobiology and Developmental Sciences
| | | | - William A Richardson
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
| | - Nicola K Gray
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, United Kingdom
| | - Gwen V Childs
- Department of Neurobiology and Developmental Sciences,; Center for Translational Neuroscience
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology,; Arkansas Children's Research Institute
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences,; Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and.
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10
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Tsujino T, Sugito N, Taniguchi K, Honda R, Komura K, Yoshikawa Y, Takai T, Minami K, Kuranaga Y, Shinohara H, Tokumaru Y, Heishima K, Inamoto T, Azuma H, Akao Y. MicroRNA-143/Musashi-2/KRAS cascade contributes positively to carcinogenesis in human bladder cancer. Cancer Sci 2019; 110:2189-2199. [PMID: 31066120 PMCID: PMC6609826 DOI: 10.1111/cas.14035] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/10/2019] [Accepted: 04/28/2019] [Indexed: 12/16/2022] Open
Abstract
It has been well established that microRNA (miR)‐143 is downregulated in human bladder cancer (BC). Recent precision medicine has shown that mutations in BC are frequently observed in FGFR3, RAS and PIK3CA genes, all of which correlate with RAS signaling networks. We have previously shown that miR‐143 suppresses cell growth by inhibiting RAS signaling networks in several cancers including BC. In the present study, we showed that synthetic miR‐143 negatively regulated the RNA‐binding protein Musashi‐2 (MSI2) in BC cell lines. MSI2 is an RNA‐binding protein that regulates the stability of certain mRNAs and their translation by binding to the target sequences of the mRNAs. Of note, the present study clarified that MSI2 positively regulated KRAS expression through directly binding to the target sequence of KRASmRNA and promoting its translation, thus contributing to the maintenance of KRAS expression. Thus, miR‐143 silenced KRAS and MSI2, which further downregulated KRAS expression through perturbation of the MSI2/KRAS cascade.
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Affiliation(s)
- Takuya Tsujino
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan.,Department of Urology, Osaka Medical College, Osaka, Japan
| | - Nobuhiko Sugito
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Kohei Taniguchi
- Translational Research Program, Osaka Medical College, Osaka, Japan
| | - Ryo Honda
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Kazumasa Komura
- Department of Urology, Osaka Medical College, Osaka, Japan.,Translational Research Program, Osaka Medical College, Osaka, Japan
| | - Yuki Yoshikawa
- Department of Urology, Osaka Medical College, Osaka, Japan
| | - Tomoaki Takai
- Department of Urology, Osaka Medical College, Osaka, Japan
| | | | - Yuki Kuranaga
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Haruka Shinohara
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Yoshihisa Tokumaru
- Department of Surgical Oncology, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Kazuki Heishima
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Teruo Inamoto
- Department of Urology, Osaka Medical College, Osaka, Japan
| | - Haruhito Azuma
- Department of Urology, Osaka Medical College, Osaka, Japan
| | - Yukihiro Akao
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
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11
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Jin Q, Liu G, Bao L, Ma Y, Qi H, Yun Z, Dai Y, Zhang S. High Spy1 expression predicts poor prognosis in colorectal cancer. Cancer Manag Res 2018; 10:2757-2765. [PMID: 30147372 PMCID: PMC6101001 DOI: 10.2147/cmar.s169329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background Spy1 (SPDYA) is a new discovered cell cycle protein capable of promoting cell proliferation dependent on cyclin-dependent kinase-2 activation. However, to the best of our knowledge, the expression of Spy1 in colorectal cancer (CRC) tissues remains virtually unknown. Materials and methods In this retrospective study, we investigated the mRNA and protein expression levels of Spy1 in CRC tissues and corresponding non-cancerous tissues with the analyses of quantitative real-time polymerase chain reaction, western blotting, and immunohistochemistry. In our research, the prognostic significances of Spy1 expression were further explored by univariate and multivariate survival analyses of 203 patients who were followed up. Results The results demonstrated that the levels of Spy1 mRNA were significantly higher in CRC tissues compared with corresponding non-cancerous tissues (p=0.0002). The results of immunohistochemistry demonstrated that the expressions of Spy1 were significantly associated with clinicopathological parameters, including T stage (χ2=7.126, p=0.028) and TNM stage (χ2=9.461, p=0.009). Kaplan-Meier analysis results indicated that high Spy1 expression (HR=2.573, p<0.001) and TNM stage (HR=1.494, p=0.011) were independent factors to predict poor prognosis for patients with CRC. Conclusion We concluded that high Spy1 expression is significantly associated with unfavorable prognosis in CRC and could serve as a potential prognostic marker in clinical diagnosis of CRC.
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Affiliation(s)
- Qin Jin
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, People's Republic of China,
| | - Gang Liu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, College of Life Science, Inner Mongolia University, Hohhot, People's Republic of China,
| | - Luri Bao
- Department of Pathology, Inner Mongolia Medical University, Hohhot, People's Republic of China
| | - Yuzhen Ma
- Centre of Reproductive Medicine, Inner Mongolia Hospital, Hohhot, People's Republic of China
| | - Huidong Qi
- Medical School of Nantong University, Nantong, People's Republic of China
| | - Zhizhong Yun
- Centre of Reproductive Medicine, Inner Mongolia Hospital, Hohhot, People's Republic of China
| | - Yanfeng Dai
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, College of Life Science, Inner Mongolia University, Hohhot, People's Republic of China,
| | - Shu Zhang
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, People's Republic of China,
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12
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Odle AK, Beneš H, Melgar Castillo A, Akhter N, Syed M, Haney A, Allensworth-James M, Hardy L, Winter B, Manoharan R, Syed R, MacNicol MC, MacNicol AM, Childs GV. Association of Gnrhr mRNA With the Stem Cell Determinant Musashi: A Mechanism for Leptin-Mediated Modulation of GnRHR Expression. Endocrinology 2018; 159:883-894. [PMID: 29228137 PMCID: PMC5776477 DOI: 10.1210/en.2017-00586] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 12/01/2017] [Indexed: 12/30/2022]
Abstract
The cyclic expression of pituitary gonadotropin-releasing hormone receptors (GnRHRs) may be an important checkpoint for leptin regulatory signals. Gonadotrope Lepr-null mice have reduced GnRHR levels, suggesting these receptors may be leptin targets. To determine if leptin stimulated GnRHR directly, primary pituitary cultures or pieces were exposed to 1 to 100 nM leptin. Leptin increased GnRHR protein levels and the percentages of gonadotropes that bound biotinylated analogs of gonadotropin-releasing hormone (bio-GnRH) but had no effect on Gnrhr messenger RNA (mRNA). An in silico analysis revealed three consensus Musashi (MSI) binding elements (MBEs) for this translational control protein in the 3' untranslated region (UTR) of Gnrhr mRNA. Several experiments determined that these Gnrhr mRNA MBE were active: (1) RNA electrophoretic mobility shift assay analyses showed that MSI1 specifically bound Gnrhr mRNA 3'-UTR; (2) RNA immunoprecipitation of pituitary fractions with MSI1 antibody pulled down a complex enriched in endogenous MSI protein and endogenous Gnrhr mRNA; and (3) fluorescence reporter assays showed that MSI1 repressed translation of the reporter coupled to the Gnrhr 3'-UTR. In vitro, leptin stimulation of pituitary pieces reduced Msi1 mRNA in female pituitaries, and leptin stimulation of pituitary cultures reduced MSI1 proteins selectively in gonadotropes identified by binding to bio-GnRH. These findings show that leptin's direct stimulatory actions on gonadotrope GnRHR correlate with a direct inhibition of expression of the posttranscriptional regulator MSI1. We also show MSI1 interaction with the 3'-UTR of Gnrhr mRNA. These findings now open the door to future studies of leptin-modulated posttranscriptional pathways.
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Affiliation(s)
- Angela K. Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Helen Beneš
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Andrea Melgar Castillo
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Noor Akhter
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Mohsin Syed
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Anessa Haney
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Melody Allensworth-James
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Linda Hardy
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Benjamin Winter
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Ragul Manoharan
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Raiyan Syed
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Melanie C. MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Angus M. MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Gwen V. Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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13
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Peuchen EH, Cox OF, Sun L, Hebert AS, Coon JJ, Champion MM, Dovichi NJ, Huber PW. Phosphorylation Dynamics Dominate the Regulated Proteome during Early Xenopus Development. Sci Rep 2017; 7:15647. [PMID: 29142207 PMCID: PMC5688136 DOI: 10.1038/s41598-017-15936-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/03/2017] [Indexed: 01/08/2023] Open
Abstract
The earliest stages of animal development are largely controlled by changes in protein phosphorylation mediated by signaling pathways and cyclin-dependent kinases. In order to decipher these complex networks and to discover new aspects of regulation by this post-translational modification, we undertook an analysis of the X. laevis phosphoproteome at seven developmental stages beginning with stage VI oocytes and ending with two-cell embryos. Concurrent measurement of the proteome and phosphoproteome enabled measurement of phosphosite occupancy as a function of developmental stage. We observed little change in protein expression levels during this period. We detected the expected phosphorylation of MAP kinases, translational regulatory proteins, and subunits of APC/C that validate the accuracy of our measurements. We find that more than half the identified proteins possess multiple sites of phosphorylation that are often clustered, where kinases work together in a hierarchical manner to create stretches of phosphorylated residues, which may be a means to amplify signals or stabilize a particular protein conformation. Conversely, other proteins have opposing sites of phosphorylation that seemingly reflect distinct changes in activity during this developmental timeline.
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Affiliation(s)
- Elizabeth H Peuchen
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Olivia F Cox
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Alex S Hebert
- Department of Chemistry, University of Wisconsin, Madison, WI, 53706, USA
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin, Madison, WI, 53706, USA
| | - Matthew M Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Paul W Huber
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
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14
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MacNicol MC, Cragle CE, McDaniel FK, Hardy LL, Wang Y, Arumugam K, Rahmatallah Y, Glazko GV, Wilczynska A, Childs GV, Zhou D, MacNicol AM. Evasion of regulatory phosphorylation by an alternatively spliced isoform of Musashi2. Sci Rep 2017; 7:11503. [PMID: 28912529 PMCID: PMC5599597 DOI: 10.1038/s41598-017-11917-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/01/2017] [Indexed: 01/06/2023] Open
Abstract
The Musashi family of RNA binding proteins act to promote stem cell self-renewal and oppose cell differentiation predominantly through translational repression of mRNAs encoding pro-differentiation factors and inhibitors of cell cycle progression. During tissue development and repair however, Musashi repressor function must be dynamically regulated to allow cell cycle exit and differentiation. The mechanism by which Musashi repressor function is attenuated has not been fully established. Our prior work indicated that the Musashi1 isoform undergoes site-specific regulatory phosphorylation. Here, we demonstrate that the canonical Musashi2 isoform is subject to similar regulated site-specific phosphorylation, converting Musashi2 from a repressor to an activator of target mRNA translation. We have also characterized a novel alternatively spliced, truncated isoform of human Musashi2 (variant 2) that lacks the sites of regulatory phosphorylation and fails to promote translation of target mRNAs. Consistent with a role in opposing cell cycle exit and differentiation, upregulation of Musashi2 variant 2 was observed in a number of cancers and overexpression of the Musashi2 variant 2 isoform promoted cell transformation. These findings indicate that alternately spliced isoforms of the Musashi protein family possess distinct functional and regulatory properties and suggest that differential expression of Musashi isoforms may influence cell fate decisions.
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Affiliation(s)
- Melanie C MacNicol
- University of Arkansas for Medical Sciences, Department of Neurobiology and Developmental Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA.,University of Arkansas for Medical Science, Center for Translational Neuroscience, 4301 W. Markham, Little Rock, 72205, AR, USA
| | - Chad E Cragle
- University of Arkansas for Medical Sciences, Department of Neurobiology and Developmental Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA
| | - F Kennedy McDaniel
- University of Arkansas for Medical Sciences, Department of Neurobiology and Developmental Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA
| | - Linda L Hardy
- University of Arkansas for Medical Sciences, Department of Neurobiology and Developmental Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA
| | - Yan Wang
- University of Arkansas for Medical Sciences, Department of Pharmaceutical Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA.,Department of Orthopedics, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 510182, PR China
| | - Karthik Arumugam
- University of Arkansas for Medical Sciences, Department of Physiology and Biophysics, 4301 W. Markham, Little Rock, 72205, AR, USA.,Center for Genomic Regulation, Department of Gene Regulation, Stem Cells and Cancer, C/Dr. Aiguader 88, 08003, Barcelona, Spain
| | - Yasir Rahmatallah
- University of Arkansas for Medical Sciences, Department of Biomedical Informatics, 4301 W. Markham, Little Rock, 72205, AR, USA
| | - Galina V Glazko
- University of Arkansas for Medical Sciences, Department of Biomedical Informatics, 4301 W. Markham, Little Rock, 72205, AR, USA
| | | | - Gwen V Childs
- University of Arkansas for Medical Sciences, Department of Neurobiology and Developmental Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA.,University of Arkansas for Medical Science, Center for Translational Neuroscience, 4301 W. Markham, Little Rock, 72205, AR, USA
| | - Daohong Zhou
- University of Arkansas for Medical Sciences, Department of Pharmaceutical Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA
| | - Angus M MacNicol
- University of Arkansas for Medical Sciences, Department of Neurobiology and Developmental Sciences, 4301 W. Markham, Little Rock, 72205, AR, USA. .,Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR, 72205, United States.
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15
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Controlling the Messenger: Regulated Translation of Maternal mRNAs in Xenopus laevis Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:49-82. [PMID: 27975270 DOI: 10.1007/978-3-319-46095-6_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The selective translation of maternal mRNAs encoding cell-fate determinants drives the earliest decisions of embryogenesis that establish the vertebrate body plan. This chapter will discuss studies in Xenopus laevis that provide insights into mechanisms underlying this translational control. Xenopus has been a powerful model organism for many discoveries relevant to the translational control of maternal mRNAs because of the large size of its oocytes and eggs that allow for microinjection of molecules and the relative ease of manipulating the oocyte to egg transition (maturation) and fertilization in culture. Consequently, many key studies have focused on the expression of maternal mRNAs during the oocyte to egg transition (the meiotic cell cycle) and the rapid cell divisions immediately following fertilization. This research has made seminal contributions to our understanding of translational regulatory mechanisms, but while some of the mRNAs under consideration at these stages encode cell-fate determinants, many encode cell cycle regulatory proteins that drive these early cell cycles. In contrast, while maternal mRNAs encoding key developmental (i.e., cell-fate) regulators that function after the first cleavage stages may exploit aspects of these foundational mechanisms, studies reveal that these mRNAs must also rely on distinct and, as of yet, incompletely understood mechanisms. These findings are logical because the functions of such developmental regulatory proteins have requirements distinct from cell cycle regulators, including becoming relevant only after fertilization and then only in specific cells of the embryo. Indeed, key maternal cell-fate determinants must be made available in exquisitely precise amounts (usually low), only at specific times and in specific cells during embryogenesis. To provide an appreciation for the regulation of maternal cell-fate determinant expression, an overview of the maternal phase of Xenopus embryogenesis will be presented. This section will be followed by a review of translational mechanisms operating in oocytes, eggs, and early cleavage-stage embryos and conclude with a discussion of how the regulation of key maternal cell-fate determinants at the level of translation functions in Xenopus embryogenesis. A key theme is that the molecular asymmetries critical for forming the body axes are established and further elaborated upon by the selective temporal and spatial regulation of maternal mRNA translation.
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16
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Pushpa K, Kumar GA, Subramaniam K. Translational Control of Germ Cell Decisions. Results Probl Cell Differ 2017; 59:175-200. [PMID: 28247049 DOI: 10.1007/978-3-319-44820-6_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Germline poses unique challenges to gene expression control at the transcriptional level. While the embryonic germline maintains a global hold on new mRNA transcription, the female adult germline produces transcripts that are not translated into proteins until embryogenesis of subsequent generation. As a consequence, translational control plays a central role in governing various germ cell decisions including the formation of primordial germ cells, self-renewal/differentiation decisions in the adult germline, onset of gametogenesis and oocyte maturation. Mechanistically, several common themes such as asymmetric localization of mRNAs, conserved RNA-binding proteins that control translation by 3' UTR binding, translational activation by the cytoplasmic elongation of the polyA tail and the assembly of mRNA-protein complexes called mRNPs have emerged from the studies on Caenorhabditis elegans, Xenopus and Drosophila. How mRNPs assemble, what influences their dynamics, and how a particular 3' UTR-binding protein turns on the translation of certain mRNAs while turning off other mRNAs at the same time and space are key challenges for future work.
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Affiliation(s)
- Kumari Pushpa
- Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Ganga Anil Kumar
- Indian Institute of Technology-Kanpur, Kanpur, India.,Indian Institute of Technology-Madras, Chennai, India
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17
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Reyes JM, Ross PJ. Cytoplasmic polyadenylation in mammalian oocyte maturation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 7:71-89. [PMID: 26596258 DOI: 10.1002/wrna.1316] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 12/21/2022]
Abstract
Oocyte developmental competence is the ability of the mature oocyte to be fertilized and subsequently drive early embryo development. Developmental competence is acquired by completion of oocyte maturation, a process that includes nuclear (meiotic) and cytoplasmic (molecular) changes. Given that maturing oocytes are transcriptionally quiescent (as are early embryos), they depend on post-transcriptional regulation of stored transcripts for protein synthesis, which is largely mediated by translational repression and deadenylation of transcripts within the cytoplasm, followed by recruitment of specific transcripts in a spatiotemporal manner for translation during oocyte maturation and early development. Motifs within the 3' untranslated region (UTR) of messenger RNA (mRNA) are thought to mediate repression and downstream activation by their association with binding partners that form dynamic protein complexes that elicit differing effects on translation depending on cell stage and interacting proteins. The cytoplasmic polyadenylation (CP) element, Pumilio binding element, and hexanucleotide polyadenylation signal are among the best understood motifs involved in CP, and translational regulation of stored transcripts as their binding partners have been relatively well-characterized. Knowledge of CP in mammalian oocytes is discussed as well as novel approaches that can be used to enhance our understanding of the functional and contributing features to transcript CP and translational regulation during mammalian oocyte maturation. WIREs RNA 2016, 7:71-89. doi: 10.1002/wrna.1316 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Juan M Reyes
- Department of Animal Science, University of California, Davis, CA, USA
| | - Pablo J Ross
- Department of Animal Science, University of California, Davis, CA, USA
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18
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Fox RG, Park FD, Koechlein CS, Kritzik M, Reya T. Musashi Signaling in Stem Cells and Cancer. Annu Rev Cell Dev Biol 2015; 31:249-67. [DOI: 10.1146/annurev-cellbio-100814-125446] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Raymond G. Fox
- Department of Pharmacology,
- Moores Cancer Center, and
- Sanford Consortium for Regenerative Medicine, La Jolla, California 92037
| | - Frederick D. Park
- Department of Pharmacology,
- Moores Cancer Center, and
- Division of Gastroenterology, University of California San Diego School of Medicine, La Jolla, California 92093;
- Sanford Consortium for Regenerative Medicine, La Jolla, California 92037
| | - Claire S. Koechlein
- Department of Pharmacology,
- Moores Cancer Center, and
- Sanford Consortium for Regenerative Medicine, La Jolla, California 92037
| | - Marcie Kritzik
- Department of Pharmacology,
- Moores Cancer Center, and
- Sanford Consortium for Regenerative Medicine, La Jolla, California 92037
| | - Tannishtha Reya
- Department of Pharmacology,
- Moores Cancer Center, and
- Sanford Consortium for Regenerative Medicine, La Jolla, California 92037
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19
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MacNicol MC, Cragle CE, Arumugam K, Fosso B, Pesole G, MacNicol AM. Functional Integration of mRNA Translational Control Programs. Biomolecules 2015. [PMID: 26197342 PMCID: PMC4598765 DOI: 10.3390/biom5031580] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Regulated mRNA translation plays a key role in control of cell cycle progression in a variety of physiological and pathological processes, including in the self-renewal and survival of stem cells and cancer stem cells. While targeting mRNA translation presents an attractive strategy for control of aberrant cell cycle progression, mRNA translation is an underdeveloped therapeutic target. Regulated mRNAs are typically controlled through interaction with multiple RNA binding proteins (RBPs) but the mechanisms by which the functions of distinct RBPs bound to a common target mRNA are coordinated are poorly understood. The challenge now is to gain insight into these mechanisms of coordination and to identify the molecular mediators that integrate multiple, often conflicting, inputs. A first step includes the identification of altered mRNA ribonucleoprotein complex components that assemble on mRNAs bound by multiple, distinct RBPs compared to those recruited by individual RBPs. This review builds upon our knowledge of combinatorial control of mRNA translation during the maturation of oocytes from Xenopus laevis, to address molecular strategies that may mediate RBP diplomacy and conflict resolution for coordinated control of mRNA translational output. Continued study of regulated ribonucleoprotein complex dynamics promises valuable new insights into mRNA translational control and may suggest novel therapeutic strategies for the treatment of disease.
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Affiliation(s)
- Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Chad E Cragle
- Interdisciplinary BioSciences Graduate Program, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Karthik Arumugam
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Bruno Fosso
- Institute of Biomembranes and Bioenergetics, National Research Council, Bari 70126, Italy.
| | - Graziano Pesole
- Institute of Biomembranes and Bioenergetics, National Research Council, Bari 70126, Italy.
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari 70125, Italy.
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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20
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Knockout of RNA Binding Protein MSI2 Impairs Follicle Development in the Mouse Ovary: Characterization of MSI1 and MSI2 during Folliculogenesis. Biomolecules 2015; 5:1228-44. [PMID: 26131972 PMCID: PMC4598749 DOI: 10.3390/biom5031228] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/29/2015] [Accepted: 06/09/2015] [Indexed: 01/20/2023] Open
Abstract
Characterizing the mechanisms underlying follicle development in the ovary is crucial to understanding female fertility and is an area of increasing research interest. The RNA binding protein Musashi is essential for post-transcriptional regulation of oocyte maturation in Xenopus and is expressed during ovarian development in Drosophila. In mammals Musashi is important for spermatogenesis and male fertility, but its role in the ovary has yet to be characterized. In this study we determined the expression of mammalian Musashi proteins MSI1 and MSI2 during mouse folliculogenesis, and through the use of a MSI2-specific knockout mouse model we identified that MSI2 is essential for normal follicle development. Time-course characterization of MSI1 and MSI2 revealed distinct differences in steady-state mRNA levels and protein expression/localization at important developmental time-points during folliculogenesis. Using a gene-trap mouse model that inactivates Msi2, we observed a significant decrease in ovarian mass, and change in follicle-stage composition due to developmental blocking of antral stage follicles and pre-antral follicle loss through atresia. We also confirmed that hormonally stimulated Msi2-deficient mice produce significantly fewer MII oocytes (60.9% less than controls, p < 0.05). Furthermore, the majority of these oocytes are of poor viability (62.2% non-viable/apoptotic, p < 0.05), which causes a reduction in female fertility evidenced by decreased litter size in Msi2-deficient animals (33.1% reduction to controls, p < 0.05). Our findings indicate that MSI1 and MSI2 display distinct expression profiles during mammalian folliculogenesis and that MSI2 is required for pre-antral follicle development.
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21
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MacNicol AM, Hardy LL, Spencer HJ, MacNicol MC. Neural stem and progenitor cell fate transition requires regulation of Musashi1 function. BMC DEVELOPMENTAL BIOLOGY 2015; 15:15. [PMID: 25888190 PMCID: PMC4369890 DOI: 10.1186/s12861-015-0064-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/26/2015] [Indexed: 12/28/2022]
Abstract
Background There is increasing evidence of a pivotal role for regulated mRNA translation in control of developmental cell fate transitions. Physiological and pathological stem and progenitor cell self-renewal is maintained by the mRNA-binding protein, Musashi1 through repression of translation of key mRNAs encoding cell cycle inhibitory proteins. The mechanism by which Musashi1 function is modified to allow translation of these target mRNAs under conditions that require inhibition of cell cycle progression, is unknown. Results In this study, we demonstrate that differentiation of primary embryonic rat neural stem/progenitor cells (NSPCs) or human neuroblastoma SH-SY5Y cells results in the rapid phosphorylation of Musashi1 on the evolutionarily conserved site serine 337 (S337). Phosphorylation of this site has been shown to be required for cell cycle control during the maturation of Xenopus oocytes. S337 phosphorylation in mammalian NSPCs and human SH-SY5Y cells correlates with the de-repression and translation of a Musashi reporter mRNA and with accumulation of protein from the endogenous Musashi target mRNA, p21WAF1/CIP1. Inhibition of Musashi regulatory phosphorylation, through expression of a phospho-inhibitory mutant Musashi1 S337A or over-expression of the wild-type Musashi, blocked differentiation of both NSPCs and SH-SY5Y cells. Musashi1 was similarly phosphorylated in NSPCs and SH-SY5Y cells under conditions of nutrient deprivation-induced cell cycle arrest. Expression of the Musashi1 S337A mutant protein attenuated nutrient deprivation-induced NSPC and SH-SY5Y cell death. Conclusions Our data suggest that in response to environmental cues that oppose cell cycle progression, regulation of Musashi function is required to promote target mRNA translation and cell fate transition. Forced modulation of Musashi1 function may present a novel therapeutic strategy to oppose pathological stem cell self-renewal.
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Affiliation(s)
- Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W. Markham, Slot 814, Little Rock, AR, 72205, USA. .,Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR, 72205, USA.
| | - Linda L Hardy
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W. Markham, Slot 814, Little Rock, AR, 72205, USA.
| | - Horace J Spencer
- Department of Biostatistics, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR, 72205, USA.
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W. Markham, Slot 814, Little Rock, AR, 72205, USA. .,Center for Translational Neuroscience, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR, 72205, USA.
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Sutherland JM, Fraser BA, Sobinoff AP, Pye VJ, Davidson TL, Siddall NA, Koopman P, Hime GR, McLaughlin EA. Developmental Expression of Musashi-1 and Musashi-2 RNA-Binding Proteins During Spermatogenesis: Analysis of the Deleterious Effects of Dysregulated Expression1. Biol Reprod 2014; 90:92. [DOI: 10.1095/biolreprod.113.115261] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Cragle C, MacNicol AM. Musashi protein-directed translational activation of target mRNAs is mediated by the poly(A) polymerase, germ line development defective-2. J Biol Chem 2014; 289:14239-51. [PMID: 24644291 DOI: 10.1074/jbc.m114.548271] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The mRNA-binding protein, Musashi, has been shown to regulate translation of select mRNAs and to control cellular identity in both stem cells and cancer cells. Within the mammalian cells, Musashi has traditionally been characterized as a repressor of translation. However, we have demonstrated that Musashi is an activator of translation in progesterone-stimulated oocytes of the frog Xenopus laevis, and recent evidence has revealed Musashi's capability to function as an activator of translation in mammalian systems. The molecular mechanism by which Musashi directs activation of target mRNAs has not been elucidated. Here, we report a specific association of Musashi with the noncanonical poly(A) polymerase germ line development defective-2 (GLD2) and map the association domain to 31 amino acids within the C-terminal domain of Musashi. We show that loss of GLD2 interaction through deletion of the binding domain or treatment with antisense oligonucleotides compromises Musashi function. Additionally, we demonstrate that overexpression of both Musashi and GLD2 significantly enhances Musashi function. Finally, we report a similar co-association also occurs between murine Musashi and GLD2 orthologs, suggesting that coupling of Musashi to the polyadenylation apparatus is a conserved mechanism to promote target mRNA translation.
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Affiliation(s)
- Chad Cragle
- From the Interdiciplinary Biomedical Sciences, Departments of Neurobiology and Developmental Sciences
| | - Angus M MacNicol
- Departments of Neurobiology and Developmental Sciences, Physiology and Biophysics, and Genetics, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 722205
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Lubanska D, Market-Velker BA, deCarvalho AC, Mikkelsen T, Fidalgo da Silva E, Porter LA. The cyclin-like protein Spy1 regulates growth and division characteristics of the CD133+ population in human glioma. Cancer Cell 2014; 25:64-76. [PMID: 24434210 DOI: 10.1016/j.ccr.2013.12.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Revised: 05/17/2013] [Accepted: 12/13/2013] [Indexed: 11/17/2022]
Abstract
The heterogeneity of brain cancers, as most solid tumors, complicates diagnosis and treatment. Identifying and targeting populations of cells driving tumorigenesis is a top priority for the cancer biology field. This is not a trivial task; considerable variance exists in the driving mutations, identifying markers, and evolutionary pressures influencing initiating cells in different individual tumors. Despite this, the ability to self-renew and differentiate must be conserved to reseed a heterogeneous tumor mass. Focusing on one example of a tumor-initiating cell population, we demonstrate that the atypical cyclin-like protein Spy1 plays a role in balancing the division properties of glioma cells with stemness properties. This mechanistic insight may provide new opportunities for therapeutic intervention of brain cancer.
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Affiliation(s)
- Dorota Lubanska
- Department of Biological Sciences, University of Windsor Ontario, Windsor, ON N9B 3P4, Canada
| | - Brenna A Market-Velker
- Department of Biological Sciences, University of Windsor Ontario, Windsor, ON N9B 3P4, Canada
| | - Ana C deCarvalho
- Department of Neurosurgery, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Tom Mikkelsen
- Department of Neurosurgery, Henry Ford Hospital, Detroit, MI 48202, USA
| | | | - Lisa A Porter
- Department of Biological Sciences, University of Windsor Ontario, Windsor, ON N9B 3P4, Canada.
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Park SM, Deering RP, Lu Y, Tivnan P, Lianoglou S, Al-Shahrour F, Ebert BL, Hacohen N, Leslie C, Daley GQ, Lengner CJ, Kharas MG. Musashi-2 controls cell fate, lineage bias, and TGF-β signaling in HSCs. ACTA ACUST UNITED AC 2014; 211:71-87. [PMID: 24395885 PMCID: PMC3892968 DOI: 10.1084/jem.20130736] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Musashi-2 is an important regulator of the hematopoietic stem cell translatome and balances HSC homeostasis and lineage bias. Hematopoietic stem cells (HSCs) are maintained through the regulation of symmetric and asymmetric cell division. We report that conditional ablation of the RNA-binding protein Msi2 results in a failure of HSC maintenance and engraftment caused by a loss of quiescence and increased commitment divisions. Contrary to previous studies, we found that these phenotypes were independent of Numb. Global transcriptome profiling and RNA target analysis uncovered Msi2 interactions at multiple nodes within pathways that govern RNA translation, stem cell function, and TGF-β signaling. Msi2-null HSCs are insensitive to TGF-β–mediated expansion and have decreased signaling output, resulting in a loss of myeloid-restricted HSCs and myeloid reconstitution. Thus, Msi2 is an important regulator of the HSC translatome and balances HSC homeostasis and lineage bias.
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Affiliation(s)
- Sun-Mi Park
- Molecular Pharmacology and Chemistry Program, 2 Center for Cell Engineering, and 3 Computational Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
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Arumugam K, Macnicol MC, Macnicol AM. Autoregulation of Musashi1 mRNA translation during Xenopus oocyte maturation. Mol Reprod Dev 2012; 79:553-63. [PMID: 22730340 DOI: 10.1002/mrd.22060] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 06/04/2012] [Indexed: 11/06/2022]
Abstract
The mRNA translational control protein, Musashi, plays a critical role in cell fate determination through sequence-specific interactions with select target mRNAs. In proliferating stem cells, Musashi exerts repression of target mRNAs to promote cell cycle progression. During stem cell differentiation, Musashi target mRNAs are de-repressed and translated. Recently, we have reported an obligatory requirement for Musashi to direct translational activation of target mRNAs during Xenopus oocyte meiotic cell cycle progression. Despite the importance of Musashi in cell cycle regulation, only a few target mRNAs have been fully characterized. In this study, we report the identification and characterization of a new Musashi target mRNA in Xenopus oocytes. We demonstrate that progesterone-stimulated translational activation of the Xenopus Musashi1 mRNA is regulated through a functional Musashi binding element (MBE) in the Musashi1 mRNA 3' untranslated region (3' UTR). Mutational disruption of the MBE prevented translational activation of Musashi1 mRNA and its interaction with Musashi protein. Further, elimination of Musashi function through microinjection of inhibitory antisense oligonucleotides prevented progesterone-induced polyadenylation and translation of the endogenous Musashi1 mRNA. Thus, Xenopus Musashi proteins regulate translation of the Musashi1 mRNA during oocyte maturation. Our results indicate that the hierarchy of sequential and dependent mRNA translational control programs involved in directing progression through meiosis are reinforced by an intricate series of nested, positive feedback loops, including Musashi mRNA translational autoregulation. These autoregulatory positive feedback loops serve to amplify a weak initiating signal into a robust commitment for the oocyte to progress through the cell cycle and become competent for fertilization.
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Affiliation(s)
- Karthik Arumugam
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, 4301W Markham, Little Rock, AR 72205, USA
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