Poly(A) metabolism and polysomal recruitment of maternal mRNAs during early Xenopus development

Paris, Jeannie; Maury, Philippe

doi:10.1016/0012-1606(90)90070-y

Cited by 142 publications

(149 citation statements)

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“…S1. Whereas roscovitine did not affect XDbf4 phosphorylation in LS extracts, we consistently observed a partial degradation of the 35 S-labeled recombinant XDbf4 (Fig. 3A).…”

Section: Identification Of the Xenopus Dbf4 And Drf1mentioning

confidence: 67%

“…3). Our inability to identify discrete phosphoisoforms of the endogenous proteins by Western blot analysis led us to follow the phosphorylation of 35 S-labeled recombinant XDbf4 and XDrf1 added to egg extracts. After incubation in interphase extract both labeled proteins exhibited a slower electrophoretic migration similar to the endogenous proteins (compare Fig.…”

Section: Identification Of the Xenopus Dbf4 And Drf1mentioning

confidence: 99%

“…35 S-Labeled in vitro translated XDbf4 and XDrf1 proteins were added to interphase (A) or mitotic (B) egg extracts in the presence or absence of 3 mM 6Ј-DMAP, 0.2 mM roscovitine (Rosco), or 1.6 M p21. After 1 h incubation at 23°C, proteins were separated by SDS-PAGE and the mobility of the 35 S-labeled proteins was visualized by phosphoimager analysis. Shrimp alkaline phosphatase (SAP) was added either before or after the 1-h incubation.…”

Section: Xdbf4 and Xdrf1 Are Only Found In Active Complexes With Xcdcmentioning

confidence: 99%

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Xenopus CDC7/DRF1 Complex Is Required for the Initiation of DNA Replication

Silva

Bradley

Gao

et al. 2006

Journal of Biological Chemistry

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The Cdc7 kinase is essential for the initiation of DNA replication in eukaryotes. Two regulatory subunits of the Xenopus Cdc7 kinase have been identified: XDbf4 and XDrf1. In this study we determined the expression pattern of XDbf4 and XDrf1 and examined their involvement in DNA replication. We show that XDrf1 expression is restricted to oogenesis and early embryos, whereas XDbf4 is expressed throughout development. Immunodepletion from Xenopus egg extracts indicated that both proteins are only found in complexes with XCdc7 and there is a 5-fold molar excess of the XCdc7/Drf1 over SCdc7/Dbf4 complexes. Both complexes exhibit kinase activity and are differentially phosphorylated during the cell cycle. Depletion of the XCdc7/Drf1 from egg extracts inhibited DNA replication, whereas depletion of XCdc7/Dbf4 had little effect. Chromatin binding studies indicated that XCdc7/Drf1 is required for pre-replication complex activation but not their assembly. XCdc7/Dbf4 complexes bound to the chromatin in two steps: the first step was independent of pre-replication complex assembly and the second step was dependent on pre-replication complex activation. By contrast, binding of XCdc7/Drf1 complexes was entirely dependent on pre-replication complex assembly. Finally, we present evidence that the association of the two complexes on the chromatin is not regulated by ATR checkpoint pathways that result from DNA replication blocks. These data suggest that Cdc7/Drf1 but not Cdc7/Dbf4 complexes support the initiation of DNA replication in Xenopus egg extracts and during early embryonic development.In eukaryotes, initiation of DNA replication requires the assembly and activation of pre-replication complexes (pre-RCs) 5 on chromatin (1). Sequential binding to DNA of the origin recognition complex, Cdc6, Cdt1, and mini-chromosome maintenance proteins (Mcm2-7) lead to formation of pre-RCs. Pre-RC activation is under the control of two kinases, Cdk2 and Cdc7, and ultimately results in the loading of replication factors such as Cdc45 and the unwinding of replication origins by the MCM helicase complex (2-5).Cdc7 is a serine/threonine kinase that is conserved from yeast to human and is essential for cell proliferation and embryonic development (6). Like CDKs (cyclin-dependent kinases), Cdc7 activity is regulated by its association with a regulatory subunit, the Dbf4 protein. This complex is often referred to as DDK (Dbf4-dependent kinase). The existence in fission yeast of a Cdc7/Dbf4 complex paralog, Spo4/Spo6, and the recent discovery of multiple Dbf4-related molecules in animal cells suggest that they belong to a novel DDK protein kinase family (7-10

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“…S1. Whereas roscovitine did not affect XDbf4 phosphorylation in LS extracts, we consistently observed a partial degradation of the 35 S-labeled recombinant XDbf4 (Fig. 3A).…”

Section: Identification Of the Xenopus Dbf4 And Drf1mentioning

confidence: 67%

Section: Identification Of the Xenopus Dbf4 And Drf1mentioning

confidence: 99%

Section: Xdbf4 and Xdrf1 Are Only Found In Active Complexes With Xcdcmentioning

confidence: 99%

See 1 more Smart Citation

Xenopus CDC7/DRF1 Complex Is Required for the Initiation of DNA Replication

Silva

Bradley

Gao

et al. 2006

Journal of Biological Chemistry

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“…3). Moreover, genetic complementation experiments showed the functional interchangeability of the Xenopus leavis eRF1 also called C11 (Paris and Philippe, 1990) and yeast Sup45 proteins (Tassan et al, 1993). Functional homology has also been shown for the human (TB-3) and Syrian hamster proteins (Urbero et al, 1997).…”

Section: Eukaryotic Release Factors 1 (Erf1)mentioning

confidence: 93%

Eukaryotic release factors (eRFs) history

Инге-Вечтомов

Zhouravleva

Maury

2003

Biology of the Cell

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112

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In the present review, we describe the history of the identification of the eukaryotic translation termination factors eRF1 and eRF3. As in the case of several proteins involved in general and essential processes in all cells (e.g., DNA replication, gene expression regulation...) the strategies and methodologies used to identify these release factors were first established in prokaryotes. The genetic investigations in Saccharomyces cerevisiae have made a major contribution in the field. A large amount of data have been produced, from which it was concluded that the SUP45 and SUP35 genes were controlling translation termination but were also involved in other functions important for the cell organization and the cell cycle accomplishment. This does not seem to be restricted to yeast but is also probably the case in eukaryotes in general. The biochemical studies of the proteins encoded by the higher eukaryote homologs of SUP45 and SUP35 were efficient and permitted the identification of eRF1 as being the key protein in the termination process, eRF3 having a stimulating role. Around 25 years were needed after the identification of sup45 and sup35 mutants for the characterization of their gene products as eRF1 and eRF3, respectively. It also has to be pointed out that if the results came first from bacteria, the identification of RF3 and eRF3 was made practically at the same time. Moreover, eRF1 was the first crystal structure obtained for a class-1 release factor, the bacterial RF2 structure came later. The goal is now to understand at the molecular level the roles of both eRF1 and eRF3 in addition to their translation termination functions.

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“…Some mRNAs, which encode such proteins as c-Mos, cyclin B1, cyclin-dependent kinase 2 (Cdk2), and the earlydevelopment-specific histone B4, are polyadenylated and translated during oocyte maturation (27-29, 33, 39). Other mRNAs, however, undergo these processes sometime after fertilization; they encode such proteins as polypeptide chain release factor (Cl1), Cl2 (function unknown), and activin receptor (28,(34)(35)(36).…”

mentioning

confidence: 99%

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

Good

Richter

1997

Molecular and Cellular Biology

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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. Cl2 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.Early development in many animals is programmed by mRNAs inherited by the egg at the time of fertilization. While many of these mRNAs are translationally dormant in oocytes, they become activated in a sequence-specific manner at subsequent developmental periods. Several mechanisms are likely to control the translation of these messages, but one that has been studied extensively in Xenopus laevis is poly(A) elongation (31). Some mRNAs, which encode such proteins as c-Mos, cyclin B1, cyclin-dependent kinase 2 (Cdk2), and the earlydevelopment-specific histone B4, are polyadenylated and translated during oocyte maturation (27-29, 33, 39). Other mRNAs, however, undergo these processes sometime after fertilization; they encode such proteins as polypeptide chain release factor (Cl1), Cl2 (function unknown), and activin receptor (28,(34)(35)(36).Both groups of mRNAs contain two cis-acting elements located in their 3Ј untranslated regions (UTRs) that are required for cytoplasmic polyadenylation. One is the virtually ubiquitous hexanucleotide AAUAAA, which is also important for nuclear pre-mRNA cleavage and polyadenylation. The second, called the cytoplasmic polyadenylation element (CPE), is a U-rich sequence located upstream of the hexanucleotide. The exact sequence of CPE differs between the two groups of mRNAs mentioned. The maturation-type CPE is UUUUUAU (consensus), whereas the embryonic CPE (eCPE) is oligo (U) 12-27 (reviewed in reference 31). At least two mRNAs that are polyadenylated in embryos also contain a third cis-acting sequence in the 3Ј UTR: the masking element that prevents precocious polyadenylation during maturation (34, 35). Because deletion of the maskin...

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Poly(A) metabolism and polysomal recruitment of maternal mRNAs during early Xenopus development

Cited by 142 publications

References 11 publications

Xenopus CDC7/DRF1 Complex Is Required for the Initiation of DNA Replication

Xenopus CDC7/DRF1 Complex Is Required for the Initiation of DNA Replication

Eukaryotic release factors (eRFs) history

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

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