scholarly journals Translational control by cytoplasmic polyadenylation of c-mos mRNA is necessary for oocyte maturation in the mouse.

1994 ◽  
Vol 13 (23) ◽  
pp. 5712-5720 ◽  
Author(s):  
F. Gebauer ◽  
W. Xu ◽  
G.M. Cooper ◽  
J.D. Richter
Keyword(s):  
Oocyte Maturation ◽  
Translational Control ◽  
Cytoplasmic Polyadenylation

scholarly journals Maturation-specific polyadenylation and translational control: diversity of cytoplasmic polyadenylation elements, influence of poly(A) tail size, and formation of stable polyadenylation complexes.

1990 ◽  
Vol 10 (11) ◽  
pp. 5634-5645 ◽  
Author(s):  
J Paris ◽  
J D Richter
Keyword(s):  
Complex Formation ◽  
Oocyte Maturation ◽  
Translational Control ◽  
Untranslated Regions ◽  
Stable Complex ◽  
Mobility Shift ◽  
Cytoplasmic Polyadenylation ◽  
Egg Extracts ◽  
Gel Mobility Shift ◽  
Rna Polyadenylation

Early embryonic development in Xenopus laevis is programmed in part by maternally derived mRNAs, many of which are translated at the completion of meiosis (oocyte maturation). Polysomal recruitment of at least one of these mRNAs, G10, is regulated by cytoplasmic poly(A) elongation which, in turn, is dependent upon the cytoplasmic polyadenylation element (CPE) UUUUUUAUAAAG and the hexanucleotide AAUAAA (L. L. McGrew, E. Dworkin-Rastl, M. B. Dworkin, and J. D. Richter, Genes Dev. 3:803-815, 1989). We have investigated whether sequences similar to the G10 RNA CPE that are present in other RNAs could also be responsible for maturation-specific polyadenylation. B4 RNA, which encodes a histone H1-like protein, requires a CPE of the sequence UUUUUAAU as well as the polyadenylation hexanucleotide. The 3' untranslated regions of Xenopus c-mos RNA and mouse HPRT RNA also contain U-rich CPEs since they confer maturation-specific polyadenylation when fused to Xenopus B-globin RNA. Polyadenylation of B4 RNA, which occurs very early during maturation, is limited to 150 residues, and it is this number that is required for polysomal recruitment. To investigate the possible diversity of factors and/or affinities that might control polyadenylation, egg extracts that faithfully adenylate exogenously added RNA were used in competition experiments. At least one factor is shared by B4 and G10 RNAs, although it has a much greater affinity for B4 RNA. Additional experiments demonstrate that an intact CPE and hexanucleotide are both required to compete for the polyadenylation apparatus. Gel mobility shift assays show that two polyadenylation complexes are formed on B4 RNA. Optimal complex formation requires an intact CPE and hexanucleotide but not ongoing adenylation. These data, plus additional RNA competition studies, suggest that stable complex formation is enhanced by an interaction of the trans-acting factors that bind the CPE and polyadenylation hexanucleotide.

Maturation-specific polyadenylation and translational control: diversity of cytoplasmic polyadenylation elements, influence of poly(A) tail size, and formation of stable polyadenylation complexes

1990 ◽  
Vol 10 (11) ◽  
pp. 5634-5645
Author(s):  
J Paris ◽  
J D Richter
Keyword(s):  
Complex Formation ◽  
Oocyte Maturation ◽  
Translational Control ◽  
Untranslated Regions ◽  
Stable Complex ◽  
Mobility Shift ◽  
Cytoplasmic Polyadenylation ◽  
Egg Extracts ◽  
Gel Mobility Shift ◽  
Rna Polyadenylation

Early embryonic development in Xenopus laevis is programmed in part by maternally derived mRNAs, many of which are translated at the completion of meiosis (oocyte maturation). Polysomal recruitment of at least one of these mRNAs, G10, is regulated by cytoplasmic poly(A) elongation which, in turn, is dependent upon the cytoplasmic polyadenylation element (CPE) UUUUUUAUAAAG and the hexanucleotide AAUAAA (L. L. McGrew, E. Dworkin-Rastl, M. B. Dworkin, and J. D. Richter, Genes Dev. 3:803-815, 1989). We have investigated whether sequences similar to the G10 RNA CPE that are present in other RNAs could also be responsible for maturation-specific polyadenylation. B4 RNA, which encodes a histone H1-like protein, requires a CPE of the sequence UUUUUAAU as well as the polyadenylation hexanucleotide. The 3' untranslated regions of Xenopus c-mos RNA and mouse HPRT RNA also contain U-rich CPEs since they confer maturation-specific polyadenylation when fused to Xenopus B-globin RNA. Polyadenylation of B4 RNA, which occurs very early during maturation, is limited to 150 residues, and it is this number that is required for polysomal recruitment. To investigate the possible diversity of factors and/or affinities that might control polyadenylation, egg extracts that faithfully adenylate exogenously added RNA were used in competition experiments. At least one factor is shared by B4 and G10 RNAs, although it has a much greater affinity for B4 RNA. Additional experiments demonstrate that an intact CPE and hexanucleotide are both required to compete for the polyadenylation apparatus. Gel mobility shift assays show that two polyadenylation complexes are formed on B4 RNA. Optimal complex formation requires an intact CPE and hexanucleotide but not ongoing adenylation. These data, plus additional RNA competition studies, suggest that stable complex formation is enhanced by an interaction of the trans-acting factors that bind the CPE and polyadenylation hexanucleotide.

scholarly journals Differential Phosphorylation Controls Maskin Association with Eukaryotic Translation Initiation Factor 4E and Localization on the Mitotic Apparatus

2005 ◽  
Vol 25 (17) ◽  
pp. 7605-7615 ◽  
Author(s):  
Daron C. Barnard ◽  
Quiping Cao ◽  
Joel D. Richter
Keyword(s):  
Oocyte Maturation ◽  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Mitotic Apparatus ◽  
Cytoplasmic Polyadenylation ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation ◽  
Differential Phosphorylation

ABSTRACT Several cytoplasmic polyadenylation element (CPE)-containing mRNAs that are repressed in Xenopus oocytes become active during meiotic maturation. A group of factors that are anchored to the CPE are responsible for this repression and activation. Two of the most important are CPEB, which binds directly to the CPE, and Maskin, which associates with CPEB. In oocytes, Maskin also binds eukaryotic translation initiation factor 4E (eIF4E), an interaction that excludes eIF4G and prevents formation of the eIF4F initiation complex. When the oocytes are stimulated to reenter the meiotic divisions (maturation), CPEB promotes cytoplasmic polyadenylation. The newly elongated poly(A) tail becomes bound by poly(A) binding protein (PABP), which in turn binds eIF4G and helps it displace Maskin from eIF4E, thereby inducing translation. Here we show that Maskin undergoes several phosphorylation events during oocyte maturation, some of which are important for its dissociation from eIF4E and translational activation of CPE-containing mRNA. These sites are T58, S152, S311, S343, S453, and S638 and are phosphorylated by cdk1. Mutation of these sites to alanine alleviates the cdk1-induced dissociation of Maskin from eIF4E. Prior to maturation, Maskin is phosphorylated on S626 by protein kinase A. While this modification has no detectable effect on translation during oocyte maturation, it is critical for this protein to localize on the mitotic apparatus in somatic cells. These results show that Maskin activity and localization is controlled by differential phosphorylation.

Translational control in early development: CPEB, P-bodies and germinal granules

2008 ◽  
Vol 36 (4) ◽  
pp. 671-676 ◽  
Author(s):  
Nancy Standart ◽  
Nicola Minshall
Keyword(s):  
Early Development ◽  
Translational Control ◽  
Binding Proteins ◽  
Rna Binding ◽  
Binding Protein ◽  
Initiation Factor ◽  
Dependent Manner ◽  
Cytoplasmic Polyadenylation ◽  
P Bodies ◽  
Germinal Granules

Selective protein synthesis in oocytes, eggs and early embryos of many organisms drives several critical aspects of early development, including meiotic maturation and entry into mitosis, establishment of embryonic axes and cell fate determination. mRNA-binding proteins which (usually) recognize 3′-UTR (untranslated region) elements in target mRNAs influence the recruitment of the small ribosomal subunit to the 5′ cap. Probably the best studied such protein is CPEB (cytoplasmic polyadenylation element-binding protein), which represses translation in the oocyte in a cap-dependent manner, and activates translation in the meiotically maturing egg, via cytoplasmic polyadenylation. Co-immunoprecipitation and gel-filtration assays revealed that CPEB in Xenopus oocytes is in a very large RNP (ribonucleoprotein) complex and interacts with other RNA-binding proteins including Xp54 RNA helicase, Pat1, RAP55 (RNA-associated protein 55) and FRGY2 (frog germ cell-specific Y-box protein 2), as well as the eIF4E (eukaryotic initiation factor 4E)-binding protein 4E-T (eIF4E-transporter) and an ovary-specific eIF4E1b, which binds the cap weakly. Functional tests which implicate 4E-T and eIF4E1b in translational repression in oocytes led us to propose a model for the specific inhibition of translation of a target mRNA by a weak cap-binding protein. The components of the CPEB RNP complex are common to P-bodies (processing bodies), neuronal granules and germinal granules, suggesting that a highly conserved ‘masking’ complex operates in early development, neurons and somatic cells.

279 CYTOPLASMIC POLYADENYLATION-REGULATED GENE EXPRESSION DURING BOVINE OOCYTE MATURATION

2015 ◽  
Vol 27 (1) ◽  
pp. 228
Author(s):  
J. M. Reyes ◽  
P. J. Ross
Keyword(s):  
Oocyte Maturation ◽  
Tail Length ◽  
Transcript Abundance ◽  
Bovine Oocyte ◽  
Rna Seq ◽  
Cytoplasmic Polyadenylation ◽  
Transcript Levels ◽  
Regulated Gene Expression ◽  
Exogenous Control

Using RNA-seq of GV and MII oocytes we have described changes in polyadenylated transcript abundance that occur during in vitro bovine oocyte maturation (Reyes J. M., J. L. Chitwood, and P. J. Ross. 2013. Deciphering regulation of transcript abundance in maturing bovine oocytes. Poster session presented at International Plant & Animal Genome XXI. San Diego, CA). These changes can be attributed to transcript degradation, transcription, or transcript polyadenylation levels. The objectives of the present study were to determine the extent of cytoplasmic polyadenylation (CP) by measuring total and polyadenylated transcript abundance and poly(A) tail length in GV and MII oocytes for 8 (CCNB1, CPEB4, DNMT3B, FBXO43, EZH2, GDF9, PRDX2, and PAIP2) genes selected based on RNA-seq results. Oocytes were obtained by aspiration of abattoir-derived ovaries (GV) and in vitro maturation for 24 h (MII). Four pools of 40 oocytes were collected per stage. Enhanced green fluorescent protein (EGFP) cRNA was spiked into each sample before RNA extraction using the PicoPure RNA Isolation Kit. Extracted RNA was equally divided for cDNA synthesis using either random hexamers or anchored oligo(dT) primers to detect total and polyadenylated transcripts, respectively. Quantitative PCR (qPCR) of target genes, EGFP (exogenous control), and PPIA (endogenous control) was performed in duplicate for each replicate and gene. Relative transcript abundance was calculated using the 2[–ΔΔC(T)] method and statistically analysed using the Student's t-test. Transcript poly(A) tail length was determined for all but 2 genes (DNMT3B and EZH2) at the GV and MII stages using rapid amplification of cDNA ends poly(A) test (RACE-PAT). Two replicates of GV (n = 100) and MII (n = 100) pairs were collected to perform RACE-PAT followed by fragment analysis on a Bioanalyzer DNA 1000 chip. Polyadenylated RNA abundance levels matched those of the RNA-seq study for 7/8 genes using both PPIA and EGFP to normalise qPCR data, demonstrating the validity of RNA-seq results. Furthermore, total transcript levels for 6/8 and 7/8 genes remained unchanged when normalized to an endogenous and exogenous control, respectively. Combined, the results suggest a significant role for CP considering changes in polyadenylated transcript levels occur without changes in total RNA abundance. Also, changes in transcript abundance corresponded to differences in poly(A) tail length at the specific stages as determined by RACE-PAT. In conclusion, CP is the predominant mechanism responsible for changes in transcript abundance during oocyte maturation at least for the majority of the examined genes, though more in-depth studies are required to determine the global extent of CP. This study improved the atlas of CP-regulated genes potentially providing researchers with critical knowledge to improve in silico tools that predict genes regulated by CP based on presence, position, and distribution of motifs within the 3′ untranslated region.

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