Functioning of the Drosophila orb gene in gurken mRNA localization and translation

The orb gene encodes an RNA recognition motif (RRM)-type RNA-binding protein that is a member of the cytoplasmic polyadenylation element binding protein (CPEB) family of translational regulators. Early in oogenesis, orb is required for the formation and initial differentiation of the egg chamber, while later in oogenesis it functions in the determination of the dorsoventral (DV) and anteroposterior axes of egg and embryo. In the studies reported here, we have examined the role of theorb gene in the gurken (grk)-Drosophila epidermal growth factor receptor (DER) signaling pathway. During the previtellogenic stages of oogenesis, the grk-DER signaling pathway defines the posterior pole of the oocyte by specifying posterior follicle cell identity. This is accomplished through the localized expression of Grk at the very posterior of the oocyte. Later in oogenesis, thegrk-DER pathway is used to establish the DV axis. Grk protein synthesized at the dorsal anterior corner of the oocyte signals dorsal fate to the overlying follicle cell epithelium. We show that orb functions in both the early and late grk-DER signaling pathways, and in each case is required for the localized expression of Grk protein. We have found thatorb is also required to promote the synthesis of a key component of the DV polarity pathway, K(10). Finally, we present evidence that Orb protein expression during the mid- to late stages of oogenesis is, in turn, negatively regulated by K(10).

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Corrigendum to: Cytoplasmic polyadenylation element binding protein 2 (CPEB2) is required for tight-junction assembly for establishment of porcine trophectoderm epithelium

Reproduction Fertility and Development ◽

10.1071/rd18098_co ◽

2019 ◽

Vol 31 (3) ◽

pp. 632

Author(s):

Jeongwoo Kwon ◽

Shuha Park ◽

Min-Jung Seong ◽

Inchul Choi ◽

Nam-Hyung Kim

Keyword(s):

Tight Junction ◽

Mrna Stability ◽

Rna Binding ◽

Binding Protein ◽

Mrna Translation ◽

Coxsackie Virus ◽

Cytoplasmic Polyadenylation ◽

Apical Cell Membrane ◽

Junction Protein ◽

Element Binding Protein

Cytoplasmic polyadenylation element binding protein (CPEB) is an RNA-binding protein that promotes elongation of poly(A) tails and regulates mRNA translation. CPEB depletion in mammary epithelium is known to disrupt tight-junction (TJ) assembly via mislocalisation of tight junction protein 1 (TJP1), but the role of CPEB in the biological functions associated with TJs has not yet been studied. The objective of this study was to investigate the roles of CPEB2 during porcine parthenote development. CPEB2 was detected in both the nuclei and apical cytoplasm at the 4- and 8-cell stages and was localised to cell–cell contact after the initiation of the morula stage. Its depletion led to retarded blastocyst formation caused by impaired TJ assembly. Moreover, transcription of TJ-associated genes, including TJP1, Coxsackie virus and adenovirus receptor (CXADR) and occludin (OCLN), was not affected, but the corresponding proteins were not properly localised at the apical cell membrane in morulae, suggesting that CPEB2 confers mRNA stability or determines subcellular localisation for translation. Remarkably reduced relative levels of TJP1 transcripts bearing the 3′-untranslated region were noted, indicating that CPEB2 mediates TJP1 mRNA stability. In conclusion, our findings demonstrate that because of its regulation of TJP1, CPEB2 is required for TJ assembly during porcine blastocyst development.

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The 36-kilodalton embryonic-type cytoplasmic polyadenylation element-binding protein in Xenopus laevis is ElrA, a member of the ELAV family of RNA-binding proteins.

Molecular and Cellular Biology ◽

10.1128/mcb.17.11.6402 ◽

1997 ◽

Vol 17 (11) ◽

pp. 6402-6409 ◽

Cited By ~ 38

Author(s):

L Wu ◽

P J Good ◽

J D Richter

Keyword(s):

Xenopus Laevis ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Binding Protein ◽

Dominant Negative ◽

Cytoplasmic Polyadenylation ◽

Element Binding Protein

The translational activation of several maternal mRNAs in Xenopus laevis is dependent on cytoplasmic poly(A) elongation. Messages harboring the UUUUUAU-type cytoplasmic polyadenylation element (CPE) in their 3' untranslated regions (UTRs) undergo polyadenylation and translation during oocyte maturation. This CPE is bound by the protein CPEB, which is essential for polyadenylation. mRNAs that have the poly(U)12-27 embryonic-type CPE (eCPE) in their 3' UTRs undergo polyadenylation and translation during the early cleavage and blastula stages. A 36-kDa eCPE-binding protein in oocytes and embryos has been identified by UV cross-linking. We now report that this 36-kDa protein is ElrA, a member of the ELAV family of RNA-binding proteins. The proteins are identical in size, antibody directed against ElrA immunoprecipitates the 36-kDa protein, and the two proteins have the same RNA binding specificity in vitro. C12 and activin receptor mRNAs, both of which contain eCPEs, are detected in immunoprecipitated ElrA-mRNP complexes from eggs and embryos. In addition, this in vivo interaction requires the eCPE. Although a number of experiments failed to define a role for ElrA in cytoplasmic polyadenylation, the expression of a dominant negative ElrA protein in embryos results in an exogastrulation phenotype. The possible functions of ElrA in gastrulation are discussed.

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Rbm24 controls poly(A) tail length and translation efficiency of crystallin mRNAs in the lens via cytoplasmic polyadenylation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1917922117 ◽

2020 ◽

Vol 117 (13) ◽

pp. 7245-7254 ◽

Cited By ~ 7

Author(s):

Ming Shao ◽

Tong Lu ◽

Chong Zhang ◽

Yi-Zhuang Zhang ◽

Shu-Hui Kong ◽

...

Keyword(s):

Rna Binding ◽

Binding Protein ◽

Wide Spectrum ◽

Tail Length ◽

Rna Recognition Motif ◽

Translation Efficiency ◽

Lens Fiber ◽

Cytoplasmic Polyadenylation ◽

Fiber Cells ◽

Lens Transparency

Lens transparency is established by abundant accumulation of crystallin proteins and loss of organelles in the fiber cells. It requires an efficient translation of lens messenger RNAs (mRNAs) to overcome the progressively reduced transcriptional activity that results from denucleation. Inappropriate regulation of this process impairs lens differentiation and causes cataract formation. However, the regulatory mechanism promoting protein synthesis from lens-expressed mRNAs remains unclear. Here we show that in zebrafish, the RNA-binding protein Rbm24 is critically required for the accumulation of crystallin proteins and terminal differentiation of lens fiber cells. In the developing lens, Rbm24 binds to a wide spectrum of lens-specific mRNAs through the RNA recognition motif and interacts with cytoplasmic polyadenylation element-binding protein (Cpeb1b) and cytoplasmic poly(A)-binding protein (Pabpc1l) through the C-terminal region. Loss of Rbm24 reduces the stability of a subset of lens mRNAs encoding heat shock proteins and shortens the poly(A) tail length of crystallin mRNAs encoding lens structural components, thereby preventing their translation into functional proteins. This severely impairs lens transparency and results in blindness. Consistent with its highly conserved expression in differentiating lens fiber cells, the findings suggest that vertebrate Rbm24 represents a key regulator of cytoplasmic polyadenylation and plays an essential role in the posttranscriptional control of lens development.

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Cytoplasmic polyadenylation element binding protein 2 (CPEB2) is required for tight-junction assembly for establishment of porcine trophectoderm epithelium

Reproduction Fertility and Development ◽

10.1071/rd18098 ◽

2019 ◽

Vol 31 (2) ◽

pp. 412 ◽

Cited By ~ 1

Author(s):

Jeongwoo Kwon ◽

Shuha Park ◽

Min-Jung Seong ◽

Inchul Choi ◽

Nam-Hyung Kim

Keyword(s):

Tight Junction ◽

Mrna Stability ◽

Rna Binding ◽

Binding Protein ◽

Mrna Translation ◽

Coxsackie Virus ◽

Cytoplasmic Polyadenylation ◽

Apical Cell Membrane ◽

Junction Protein ◽

Element Binding Protein

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Novel RNA recognition motif domain in the cytoplasmic polyadenylation element binding protein 3

Proteins Structure Function and Bioinformatics ◽

10.1002/prot.24651 ◽

2014 ◽

Vol 82 (10) ◽

pp. 2879-2886 ◽

Cited By ~ 3

Author(s):

Kengo Tsuda ◽

Kanako Kuwasako ◽

Takashi Nagata ◽

Mari Takahashi ◽

Takanori Kigawa ◽

...

Keyword(s):

Binding Protein ◽

Rna Recognition Motif ◽

Rna Recognition ◽

Cytoplasmic Polyadenylation ◽

Recognition Motif ◽

Element Binding Protein

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The low complexity motif of cytoplasmic polyadenylation element binding protein 3 (CPEB3) is critical for the trafficking of its targets in neurons

10.1101/2020.05.16.100032 ◽

2020 ◽

Cited By ~ 1

Author(s):

Lenzie Ford ◽

Arun Asok ◽

Arielle D. Tripp ◽

Cameron Parro ◽

Michelle Fitzpatrick ◽

...

Keyword(s):

Rna Binding ◽

Binding Protein ◽

Low Complexity ◽

Long Term Memory ◽

Cytoplasmic Polyadenylation ◽

Term Memory ◽

Local Protein Synthesis ◽

Element Binding Protein ◽

Local Protein

SummaryBiomolecular condensates, membraneless organelles found throughout the cell, play critical roles in many aspects of cellular function. Ribonucleoprotein granules (RNPs), a type of biomolecular condensate found in neurons that are necessary for local protein synthesis and are involved in long-term potentiation (LTP). Several RNA-binding proteins present in RNPs are necessary for the synaptic plasticity involved in LTP and long-term memory. Most of these proteins possess low complexity motifs, allowing for increased promiscuity. We explore the role the low complexity motif plays for RNA binding protein cytoplasmic polyadenylation element binding protein 3 (CPEB3), a protein necessary for long-term memory persistence. We found that RNA binding and SUMOylation are necessary for CPEB3 localization to the P body, thereby having functional implications on translation. Here, we investigate the role of the low complexity motif of CPEB3 and find that it is necessary for P body localization and downstream targeting for local protein synthesis.

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Identification of RNA-binding proteins specific to Xenopus Eg maternal mRNAs: association with the portion of Eg2 mRNA that promotes deadenylation in embryos

Development ◽

10.1242/dev.116.4.1193 ◽

1992 ◽

Vol 116 (4) ◽

pp. 1193-1202

Author(s):

V. Legagneux ◽

P. Bouvet ◽

F. Omilli ◽

S. Chevalier ◽

H.B. Osborne

Keyword(s):

Untranslated Region ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Binding Protein ◽

Untranslated Regions ◽

Cytoplasmic Polyadenylation ◽

Element Binding Protein ◽

Maternal Mrnas ◽

Post Transcriptional Regulation

Maternal Xenopus Eg mRNAs have been previously identified as transcripts that are specifically deadenylated after fertilization and degraded after the mid blastula transition. Destabilizing cis sequences were previously localised in the 3′ untranslated region of Eg2 mRNA. In order to characterize possible trans-acting factors which are involved in the post-transcriptional regulation of Eg mRNAs, gel-shift and u.v. cross-linking experiments were performed, which allowed the identification of a p53-p55 RNA-binding protein doublet specific for the 3′ untranslated regions of Eg mRNAs. These p53-p55 proteins do not bind to the 3′ untranslated regions of either ornithine decarboxylase or phosphatase 2Ac mRNAs, which remain polyadenylated in embryos. These novel RNA-binding proteins are distinct from the cytoplasmic polyadenylation element-binding protein that controls the polyadenylation of maternal mRNAs in maturing Xenopus oocytes, and from previously identified thermoresistant RNA-binding proteins present in oocyte mRNP storage particles. The p53-p55 bind a portion of the Eg2 mRNA 3′ untranslated region, distinct from the previously identified destabilizing region, that is able to confer the postfertilization deadenylation of CAT-coding chimeric mRNAs. This suggests that the p53-p55 RNA-binding proteins are good candidates for trans-acting factors involved in the deadenylation of Eg mRNAs in Xenopus embryos.

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RNA recognition and self-association of CPEB4 is mediated by its tandem RRM domains

Nucleic Acids Research ◽

10.1093/nar/gku700 ◽

2014 ◽

Vol 42 (15) ◽

pp. 10185-10195 ◽

Cited By ~ 4

Author(s):

Constanze Schelhorn ◽

James M.B. Gordon ◽

Lidia Ruiz ◽

Javier Alguacil ◽

Enrique Pedroso ◽

...

Keyword(s):

Rna Binding ◽

Titration Calorimetry ◽

Rna Recognition Motif ◽

Rna Recognition ◽

Mobility Shift ◽

Cytoplasmic Polyadenylation ◽

C Terminus ◽

Self Association ◽

Mobility Shift Assay ◽

A Minor

Abstract Cytoplasmic polyadenylation is regulated by the interaction of the cytoplasmic polyadenylation element binding proteins (CPEB) with cytoplasmic polyadenylation element (CPE) containing mRNAs. The CPEB family comprises four paralogs, CPEB1–4, each composed of a variable N-terminal region, two RNA recognition motif (RRM) and a C-terminal ZZ-domain. We have characterized the RRM domains of CPEB4 and their binding properties using a combination of biochemical, biophysical and NMR techniques. Isothermal titration calorimetry, NMR and electrophoretic mobility shift assay experiments demonstrate that both the RRM domains are required for an optimal CPE interaction and the presence of either one or two adenosines in the two most commonly used consensus CPE motifs has little effect on the affinity of the interaction. Both the single RRM1 and the tandem RRM1–RRM2 have the ability to dimerize, although representing a minor population. Self-association does not affect the proteins’ ability to interact with RNA as demonstrated by ion mobility–mass spectrometry. Chemical shift effects measured by NMR of the apo forms of the RRM1–RRM2 samples indicate that the two domains are orientated toward each other. NMR titration experiments show that residues on the β-sheet surface on RRM1 and at the C-terminus of RRM2 are affected upon RNA binding. We propose a model of the CPEB4 RRM1–RRM2–CPE complex that illustrates the experimental data.

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