Identification of a novel Xenopus laevis poly (A) binding protein

Cosson, Bertrand; Braun, Frédérique; Paillard, Luc; Blackshear, Perry J.; Osborne, Howard Beverley

doi:10.1016/j.biolcel.2004.04.006

Cited by 20 publications

(20 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Very recently, two groups (45,48) independently identified a PABP in Xenopus with 50% amino acid identity to Xenopus PABPN1, called ePABP2. Unlike PABPN1, ePABP2 is localized to the cytoplasm.…”

Section: Discussionmentioning

confidence: 99%

“…These observations suggest that ePABP2, like ePAB, may play a role in the cytoplasmic polyadenylation of mRNAs. However, it is noteworthy that Xenopus ePABP2 is present for a much longer period than ePAB (45,48), suggesting that the control of its expression may be independent of ZGA. Moreover, Xenopus ePABP2, unlike Xenopus ePAB, is not able to interact with the cap-binding complex and is therefore unlikely to stimulate translation at the initiation step (48).…”

Section: Discussionmentioning

confidence: 99%

“…Then the replacement of ePABP2 by ePAB would allow the initiation of mRNA translation. Such an exchange of PABN1 for PABP1 occurs in somatic cells upon transport into the cytoplasm of nuclear 3Ј end-processed mRNA (48). Further studies are necessary to determine the exact role of the various cytoplasmic embryonic PABPs in the translational activation of maternally derived mRNAs.…”

Section: Discussionmentioning

confidence: 99%

“…PABPN1 is a nuclear protein required for processive elongation of the poly(A) tail and control of its length during pre-mRNA processing (46,47). An embryonic, cytoplasmic form of this protein (ePABP2), which may be involved in cytoplasmic poly(A) tail elongation, has recently been described in Xenopus and mouse (45,48).…”

mentioning

confidence: 99%

See 3 more Smart Citations

An embryonic poly(A)-binding protein (ePAB) is expressed in mouse oocytes and early preimplantation embryos

Seli

Lalioti

Flaherty

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

119

View full text Add to dashboard Cite

Gene expression during oocyte maturation, fertilization, and early embryo development until zygotic gene activation is regulated mainly by translational activation of maternally derived mRNAs. This process requires the presence of a poly(A)-binding protein. However, the cytoplasmic somatic cell poly(A)-binding protein (PABP1) is not expressed until later in embryogenesis. We recently identified an embryonic poly(A)-binding protein (ePAB) in Xenopus. ePAB is the predominant cytoplasmic PABP in Xenopus oocytes and early embryos and prevents deadenylation of mRNAs, suggesting its importance in the regulation of gene expression during early Xenopus development. Here we report the identification of the mouse ortholog of Xenopus ePAB. The mouse ePAB gene on chromosome 2 contains 14 exons that specify an alternatively spliced mRNA encoding a protein of 608 or 561 aa with Ϸ65% identity to Xenopus ePAB. Mouse ePAB mRNA is expressed in ovaries and testis but not in somatic tissues. In situ hybridization localizes ePAB RNA to oocytes and confirms its absence from surrounding somatic cells in the mouse ovary. During early development, mouse ePAB is expressed in prophase I and metaphase II oocytes and one-cell and two-cell embryos and then becomes undetectable in four-or-more-cell embryos. In contrast, PABP1 mRNA expression is minimal in oocytes and early embryos until the eight-cell stage when it increases, becoming predominant at the blastocyst stage. The expression of mouse ePAB before zygotic gene activation argues for its importance in translational activation of maternally derived mRNAs during mammalian oocyte and early preimplantation embryo development.translational activation ͉ embryogenesis ͉ oogenesis M echanisms for establishing the germline and carrying out oogenesis in evolutionarily distant animals exhibit common themes. Gametes develop from primordial germ cells that are set aside during early embryogenesis (1). In most metazoans, primordial germ cells have an extragonadal origin and migrate to reach the somatic gonad, where they proliferate by mitosis to form oocytes (1). Oocytes, in turn, enter meiosis only to be arrested at the prophase of the first meiotic division (2, 3). This first meiotic arrest may last up to a few years in Xenopus and several decades in humans and is characterized by synthesis and storage of large quantities of dormant mRNA (4, 5). The resumption of meiosis is stimulated by progesterone in Xenopus (6, 7) or by gonadotropins in mouse and human (8, 9) and marks the onset of oocyte maturation.Oocyte maturation is accompanied by a complex network of translational activation and repression of dormant maternal mRNAs (10-13), whereas transcription is limited at best. These maternal mRNAs drive the oocyte's reentry into meiosis and control the rate of mitosis during the early cleavage divisions of the embryo (13-16). The transcriptional silencing that begins with oocyte maturation persists during the initial mitotic divisions of the embryonic cells. In Xenopus, after 12 rapid synchronous cle...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

An embryonic poly(A)-binding protein (ePAB) is expressed in mouse oocytes and early preimplantation embryos

Seli

Lalioti

Flaherty

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

119

View full text Add to dashboard Cite

show abstract

“…The addition of a sufficient excess of Y-box proteins into in vitro translation systems leads to a translational repression of reporter mRNAs (20 -22). Later studies identified other components of mRNPs, including a DEAD-box ATPase Xp54 and embryonic poly(A)-binding proteins, ePAB and ePABP2 (23)(24)(25)(26)(27). Xp54 and its human homologue RCK repress translation in vitro and/or in oocytes (28,29).…”

mentioning

confidence: 99%

RAP55, a Cytoplasmic mRNP Component, Represses Translation in Xenopus Oocytes

Tanaka

Ogawa

Takagi

et al. 2006

Journal of Biological Chemistry

107

128

View full text Add to dashboard Cite

mRNAs in eukaryotic cells are presumed to always associate with a set of proteins to form mRNPs. In Xenopus oocytes, a large pool of maternal mRNAs is masked from the translational apparatus as storage mRNPs. Here we identified Xenopus RAP55 (xRAP55) as a component of RNPs that associate with FRGY2, the principal component of maternal mRNPs. RAP55 is a member of the Scd6 or Lsm14 family. RAP55 localized to cytoplasmic foci in Xenopus oocytes and the processing bodies (P-bodies) in cultured human cells: in the latter cells, RAP55 is an essential constituent of the P-bodies. We isolated xRAP55-containing complexes from Xenopus oocytes and identified xRAP55-associated proteins, including a DEAD-box protein, Xp54, and a protein arginine methyltransferase, PRMT1. Recombinant xRAP55 repressed translation, together with Xp54, in an in vitro translation system. In addition, xRAP55 repressed translation in oocytes when tethered with a reporter mRNA. Domain analyses revealed that the N-terminal region of RAP55, including the Lsm domain, is important for the localization to P-bodies and translational repression. Taken together, our results suggest that xRAP55 is involved in translational repression of mRNA as a component of storage mRNPs.

show abstract

Analysis of mRNA associated factors during bovine oocyte maturation and early embryonic development

Siemer

Smiljaković

Bhojwani

et al. 2009

Molecular Reproduction Devel

View full text Add to dashboard Cite

Regulation of gene expression at the translational level is particularly essential during developmental periods, when transcription is impaired. According to the closed-loop model of translational initiation, we have analyzed components of the 5 -mRNA cap-binding complex eIF4F (eIF4E, eIF4G, eIF4A), the eIF4E repressor 4E-BP1, and 3 -mRNA poly-(A) tail-associated proteins (PABP1 and 3, PAIP1 and 2, CPEB1, Maskin) during in vitro maturation of bovine oocytes and early embryonic development up to the 16-cell stage. Furthermore, we have elucidated the activity of distinct kinases which are potentially involved in their phosphorylation. Major phosphorylation of specific target sequences of PKA, PKB, PKC, CDKs, ATM/ATR, and MAPK were observed in M II stage oocytes. Furthermore, main changes in the abundance and/or phosphorylation of distinct mRNA-binding factors occur at the transition from M II stage oocytes to 2-cell embryos. In conclusion, the results indicate that, at the transition from oocyte to embryonic development, translational initiation is regulated by striking differences in the abundance and/or phosphorylation of 5 -end and 3 -end mRNA associated factors, mainly the poly-(A) bindings proteins PABP1 and 3, their repressor PAIP2 and a Maskin-like protein with distinct eIF4E-binding properties which prevents eIF4E/cap binding and eIF4F formation in vitro. Nevertheless, from the M II stage to 16-cell embryos a substantial amount of eIF4E and, to a lesser extent, of eIF4G was precipitated by (7)m-GTP-Separose indicating eIF4F complex formation. Therefore, it is likely that in general the reduction in PABP1 and 3 abundance represses overall translation during early embryonic development.

show abstract

Identification of a novel Xenopus laevis poly (A) binding protein

Cited by 20 publications

References 43 publications

An embryonic poly(A)-binding protein (ePAB) is expressed in mouse oocytes and early preimplantation embryos

An embryonic poly(A)-binding protein (ePAB) is expressed in mouse oocytes and early preimplantation embryos

RAP55, a Cytoplasmic mRNP Component, Represses Translation in Xenopus Oocytes

Analysis of mRNA associated factors during bovine oocyte maturation and early embryonic development

Contact Info

Product

Resources

About