scholarly journals Changes in subcellular structures and states of pumilio 1 regulate the translation of target Mad2 and cyclin B1 mRNAs

2020 ◽  
Vol 133 (23) ◽  
pp. jcs249128
Author(s):  
Natsumi Takei ◽  
Yuki Takada ◽  
Shohei Kawamura ◽  
Keisuke Sato ◽  
Atsushi Saitoh ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Rna Binding ◽  
Mrna Translation ◽  
Cyclin B1 ◽  
Spatial Control ◽  
Major Mechanism ◽  
Target Mrnas ◽  
Dissolution Model ◽  
Translational Activation ◽  
Temporal And Spatial

ABSTRACTTemporal and spatial control of mRNA translation has emerged as a major mechanism for promoting diverse biological processes. However, the molecular nature of temporal and spatial control of translation remains unclear. In oocytes, many mRNAs are deposited as a translationally repressed form and are translated at appropriate times to promote the progression of meiosis and development. Here, we show that changes in subcellular structures and states of the RNA-binding protein pumilio 1 (Pum1) regulate the translation of target mRNAs and progression of oocyte maturation. Pum1 was shown to bind to Mad2 (also known as Mad2l1) and cyclin B1 mRNAs, assemble highly clustered aggregates, and surround Mad2 and cyclin B1 RNA granules in mouse oocytes. These Pum1 aggregates were dissolved prior to the translational activation of target mRNAs, possibly through phosphorylation. Stabilization of Pum1 aggregates prevented the translational activation of target mRNAs and progression of oocyte maturation. Together, our results provide an aggregation-dissolution model for the temporal and spatial control of translation.

scholarly journals Changes in subcellular structures and states of Pumilio1 regulate the translation of target Mad2 and Cyclin B1 mRNAs

2020 ◽  
Author(s):  
Natsumi Takei ◽  
Yuki Takada ◽  
Shohei Kawamura ◽  
Atsushi Saitoh ◽  
Jenny Bormann ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Rna Binding ◽  
Mrna Translation ◽  
Cyclin B1 ◽  
Spatial Control ◽  
Major Mechanism ◽  
Target Mrnas ◽  
Dissolution Model ◽  
Translational Activation ◽  
Temporal And Spatial

AbstractTemporal and spatial control of mRNA translation has emerged as a major mechanism for promoting diverse biological processes. However, the molecular nature of temporal control of translation remains unclear. In oocytes, many mRNAs are deposited as a translationally repressed form and are translated at appropriate timings to promote the progression of meiosis and development. Here, we show that changes in structures and states of the RNA-binding protein Pumilio1 regulate the translation of target mRNAs and progression of oocyte maturation. Pumilio1 was shown to bind to Mad2 and Cyclin B1 mRNAs, assemble highly clustered solid-like aggregates, and surround Mad2 and Cyclin B1 RNA granules in mouse oocytes. These Pumilio1 aggregates were dissolved by phosphorylation prior to the translational activation of target mRNAs. Stabilization of Pumilio1 aggregates prevented the translational activation of target mRNAs and oocyte maturation. Together, our results provide an aggregation-dissolution model for the temporal and spatial control of translation.

scholarly journals Musashi interaction with poly(A)-binding protein is required for activation of target mRNA translation

2019 ◽  
Vol 294 (28) ◽  
pp. 10969-10986 ◽  
Author(s):  
Chad E. Cragle ◽  
Melanie C. MacNicol ◽  
Stephanie D. Byrum ◽  
Linda L. Hardy ◽  
Samuel G. Mackintosh ◽  
...  
Keyword(s):  
Stem Cell ◽  
Oocyte Maturation ◽  
Binding Protein ◽  
Control Cell ◽  
Ectopic Expression ◽  
Mrna Translation ◽  
Stem Cell Differentiation ◽  
Target Mrna ◽  
Target Mrnas ◽  
Translational Activation

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.

scholarly journals Cyclin B1 mRNA translation is temporally controlled through formation and disassembly of RNA granules

2013 ◽  
Vol 202 (7) ◽  
pp. 1041-1055 ◽  
Author(s):  
Tomoya Kotani ◽  
Kyota Yasuda ◽  
Ryoma Ota ◽  
Masakane Yamashita
Keyword(s):  
Real Time ◽  
Oocyte Maturation ◽  
Translational Control ◽  
Actin Filaments ◽  
Messenger Rna ◽  
Mrna Translation ◽  
Cyclin B1 ◽  
Granule Formation ◽  
Rna Granules ◽  
Translational Activation

Temporal control of messenger RNA (mRNA) translation is an important mechanism for regulating cellular, neuronal, and developmental processes. However, mechanisms that coordinate timing of translational activation remain largely unresolved. Full-grown oocytes arrest meiosis at prophase I and deposit dormant mRNAs. Of these, translational control of cyclin B1 mRNA in response to maturation-inducing hormone is important for normal progression of oocyte maturation, through which oocytes acquire fertility. In this study, we found that dormant cyclin B1 mRNA forms granules in the cytoplasm of zebrafish and mouse oocytes. Real-time imaging of translation revealed that the granules disassemble at the time of translational activation during maturation. Formation of cyclin B1 RNA granules requires binding of the mRNA to Pumilio1 protein and depends on actin filaments. Disruption of cyclin B1 RNA granules accelerated the timing of their translational activation after induction of maturation, whereas stabilization hindered translational activation. Thus, our results suggest that RNA granule formation is critical for the regulation of timing of translational activation.

scholarly journals The RNA-binding protein DAZL functions as repressor and activator of mRNA translation during oocyte maturation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Cai-Rong Yang ◽  
Gabriel Rajkovic ◽  
Enrico Maria Daldello ◽  
Xuan G. Luong ◽  
Jing Chen ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Mrna Translation

scholarly journals The Cell Fate Determinant Musashi Is Controlled Through Dynamic Protein:Protein Interactions

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A555-A555
Author(s):  
Katherine Bronson ◽  
Meenakshisundaram Balasubramaniam ◽  
Linda Hardy ◽  
Gwen V Childs ◽  
Melanie C MacNicol ◽  
...  
Keyword(s):  
Cell Fate ◽  
Oocyte Maturation ◽  
Rna Binding ◽  
Mrna Translation ◽  
Hormone Production ◽  
Target Mrna ◽  
Associated Proteins ◽  
Specific Regulation ◽  
Partner Proteins

Abstract The Musashi RNA-binding protein functions as a gatekeeper of cell maturation and plasticity through the control of target mRNA translation. It is understood that Musashi promotes stem cell self-renewal and opposes differentiation. While Musashi is best characterized as a repressor of target mRNA translation, we have shown that Musashi can activate target mRNA translation in a cell context specific manner via regulatory phosphorylation on two evolutionarily conserved C-terminal serine residues. Our recent work has found that Musashi is expressed in pituitary stem cells as well as in differentiated hormone producing cell lineages in the adult pituitary. We hypothesize that Musashi maintains cell fate plasticity in the adult pituitary to allow the gland to modulate hormone production in response to changing organismal needs. Here, we seek to understand the regulation of Musashi function. Both Musashi isoforms (Musashi1 and Musashi2) contain two RNA-recognition motifs (RRMs) that bind to specific sequences in the 3’-UTR of target mRNA transcripts; however, neither isoform has enzymatic properties and thus functions through interactions with other proteins to regulate translational outcomes, but the identity and role of Musashi partner proteins is largely unknown. In this study, we have identified co-associated partner proteins that functionally contribute to Musashi-dependent mRNA translational activation during the maturation of Xenopus oocytes. Using mass spectrometry, we identified 29 co-associated proteins that interact specifically with Musashi1 during oocyte maturation and determined that the Musashi co-associated proteins ePABP, PABP4, LSM14A/B, CELF2, PUM1, ELAV1, ELAV2, and DDX6 attenuated oocyte maturation through individual antisense DNA oligo knockdowns. An assessment of the role of these cofactors in the control of Musashi-dependent target mRNA translation is in progress. In addition to studying co-associated proteins, we have created a computational 3D model of the Musashi1 molecule to assist in our investigation Musashi dimerization. This model has indicated that both Musashi1 dimerization and Musashi1:Musashi2 heterodimerization are energetically favorable, and co-pulldown studies have verified both Musashi1 homo-dimerization and Musashi1:Musashi2 heterodimerization in vivo. Computational modeling of Musashi dimer complexes has also identified the key amino acids necessary for these interactions. The contribution of each co-associated protein’s influence on Musashi-dependent translation, relative to the requirement for Musashi:Musashi dimerization, is expected to provide unparalleled insight into regulation of Musashi action. Moreover, cell type specific regulation of association of Musashi co-factors would directly influence Musashi target mRNA translation in oocyte maturation and during pituitary cell plasticity.

scholarly journals The Control of Cyclin B1 mRNA Translation during Mouse Oocyte Maturation

2000 ◽  
Vol 221 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Joyce Tay ◽  
Rebecca Hodgman ◽  
Joel D. Richter
Keyword(s):  
Oocyte Maturation ◽  
Mrna Translation ◽  
Cyclin B1 ◽  
Mouse Oocyte

scholarly journals Embryonic poly(A)-binding protein (EPAB) is required for oocyte maturation and female fertility in mice

2012 ◽  
Vol 446 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Ozlem Guzeloglu-Kayisli ◽  
Maria D. Lalioti ◽  
Fulya Aydiner ◽  
Isaac Sasson ◽  
Orkan Ilbay ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Binding Protein ◽  
Germinal Vesicle ◽  
Cyclin B1 ◽  
Female Fertility ◽  
Prostaglandin Synthase ◽  
Translational Activation ◽  
Factor Α

Gene expression during oocyte maturation and early embryogenesis up to zygotic genome activation requires translational activation of maternally-derived mRNAs. EPAB [embryonic poly(A)-binding protein] is the predominant poly(A)-binding protein during this period in Xenopus, mouse and human. In Xenopus oocytes, ePAB stabilizes maternal mRNAs and promotes their translation. To assess the role of EPAB in mammalian reproduction, we generated Epab-knockout mice. Although Epab−/− males and Epab+/− of both sexes were fertile, Epab−/− female mice were infertile, and could not generate embryos or mature oocytes in vivo or in vitro. Epab−/− oocytes failed to achieve translational activation of maternally-stored mRNAs upon stimulation of oocyte maturation, including Ccnb1 (cyclin B1) and Dazl (deleted in azoospermia-like) mRNAs. Microinjection of Epab mRNA into Epab−/− germinal vesicle stage oocytes did not rescue maturation, suggesting that EPAB is also required for earlier stages of oogenesis. In addition, late antral follicles in the ovaries of Epab−/− mice exhibited impaired cumulus expansion, and a 8-fold decrease in ovulation, associated with a significant down-regulation of mRNAs encoding the EGF (epidermal growth factor)-like growth factors Areg (amphiregulin), Ereg (epiregulin) and Btc (betacellulin), and their downstream regulators, Ptgs2 (prostaglandin synthase 2), Has2 (hyaluronan synthase 2) and Tnfaip6 (tumour necrosis factor α-induced protein 6). The findings from the present study indicate that EPAB is necessary for oogenesis, folliculogenesis and female fertility in mice.

144. ROLE OF RNA-BINDING PROTEIN, MUSASHI-1 (Msi-1), IN MURINE FOLLICULOGENESIS AND OOCYTE DEVELOPMENT

2009 ◽  
Vol 21 (9) ◽  
pp. 62
Author(s):  
K. M. Gunter ◽  
B. A. Fraser ◽  
A. P. Sobinoff ◽  
N. A. Siddall ◽  
G. R. Hime ◽  
...  
Keyword(s):  
Real Time ◽  
Oocyte Maturation ◽  
Real Time Pcr ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Mrna Translation ◽  
Oocyte Development ◽  
Target Mrna ◽  
P21 Waf1

Follicular development and oocyte maturation in mammals requires the temporal and spatial control of protein production. Consequently, it is hypothesised that the preovulatory follicle represses mRNA translation until specific proteins are required during oocyte maturation. Increasingly RNA-binding proteins are being recognised as important contributors to germ cell development, particularly during oocyte transcriptional quiescence. We have identified the presence of RNA-binding protein musashi-1 (Msi-1) mRNA within the mouse ovary and mature mouse oocyte, where the protein is believed to act as a translational repressor by binding to specific sequences within the 3' UTR of target mRNA molecules. Recent studies in various mammalian systems have identified p21 WAF1, cdkn2a, notch and m-numb as potential targets of Msi-1. We have also identified morf4l1 as a potential target through preliminary pulldown and microarray analysis using a GST tagged Msi-1 recombinant protein. To further study these potential targets, a transgenic Msi-1 mouse was produced to overexpress the RNA-binding protein in the developing oocyte. Real time PCR, performed on intact ovaries of WT and Tg mice, has so far demonstrated a 1.5-fold increase in Msi-1 expression in tgMsi-1/+ ovaries, above WT ovary expression. Real time PCR analysis of Msi-1 target mRNA expression has also shown an overall increase in expression in the tgMsi-1/+ ovaries of p21 WAF1 (~2.5-fold), cdkn2a (~2-fold), and notch (~3-fold). However m-numb and morf4l1 do not appear to be targets of Msi-1 in the oocyte, with no significant difference in expression between the WT and tgMsi-1/+ ovaries analysed. Functional quantification of oocyte development reveals a significantly less oocytes produced from superovulated juvenile mice compared with wild type litter mates. Therefore, preliminary analysis suggests that Msi-1 may play a role in binding the transcripts of genes necessary for cell cycle regulation and chromatin remodelling, characteristic of meiotic progression and oocyte development.

scholarly journals Viral and cellular mRNA-specific activators harness PABP and eIF4G to promote translation initiation downstream of cap binding

2017 ◽  
Vol 114 (24) ◽  
pp. 6310-6315 ◽  
Author(s):  
Richard W. P. Smith ◽  
Ross C. Anderson ◽  
Osmany Larralde ◽  
Joel W. S. Smith ◽  
Barbara Gorgoni ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Control Point ◽  
Ribosomal Subunit ◽  
Mrna Translation ◽  
Initiation Factor ◽  
Dependent Manner ◽  
Translational Activation

Regulation of mRNA translation is a major control point for gene expression and is critical for life. Of central importance is the complex between cap-bound eukaryotic initiation factor 4E (eIF4E), eIF4G, and poly(A) tail-binding protein (PABP) that circularizes mRNAs, promoting translation and stability. This complex is often targeted to regulate overall translation rates, and also by mRNA-specific translational repressors. However, the mechanisms of mRNA-specific translational activation by RNA-binding proteins remain poorly understood. Here, we address this deficit, focusing on a herpes simplex virus-1 protein, ICP27. We reveal a direct interaction with PABP that is sufficient to promote PABP recruitment and necessary for ICP27-mediated activation. PABP binds several translation factors but is primarily considered to activate translation initiation as part of the PABP–eIF4G–eIF4E complex that stimulates the initial cap-binding step. Importantly, we find that ICP27-PABP forms a complex with, and requires the activity of, eIF4G. Surprisingly, ICP27–PABP–eIF4G complexes act independently of the effects of PABP-eIF4G on cap binding to promote small ribosomal subunit recruitment. Moreover, we find that a cellular mRNA-specific regulator, Deleted in Azoospermia-like (Dazl), also employs the PABP–eIF4G interaction in a similar manner. We propose a mechanism whereby diverse RNA-binding proteins directly recruit PABP, in a non–poly(A) tail-dependent manner, to stimulate the small subunit recruitment step. This strategy may be particularly relevant to biological conditions associated with hypoadenylated mRNAs (e.g., germ cells/neurons) and/or limiting cytoplasmic PABP (e.g., viral infection, cell stress). This mechanism adds significant insight into our knowledge of mRNA-specific translational activation and the function of the PABP–eIF4G complex in translation initiation.

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