Identification of a Novel mRNA-Associated Protein in Oocytes ofPleurodeles waltlandXenopus laevis

Lieb, Bernhard; Carl, Marina; Hock, Robert; Gebauer, Dagmar; Scheer, Ulrich

doi:10.1006/excr.1998.4249

Cited by 36 publications

(31 citation statements)

References 37 publications

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“…We have also reported that microinjection with Xoom antisense RNA causes inhibition of the epibolic cell elongation in the outer ectodermal layer through disorganization of F-actin without any disruption to mesodermal gene expression (Hasegawa & Kinoshita 2000). The (Murray et al 1992;Goodman et al 1998;Lieb et al 1998;Stennard et al 1999 (Hasegawa et al 1999).…”

Section: Discussionmentioning

confidence: 93%

Xoom is maternally stored and functions as a transmembrane protein for gastrulation movement in Xenopus embryos

2001

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Xoom has been identified as a novel gene that plays an important role in gastrulation of Xenopus laevis embryo. Although Xoom is actively transcribed during oogenesis, distribution and function of its translation product have not yet been clarified. In the present study, the polyclonal antibody raised against Xoom was generated to investigate a behavior of Xoom protein. Anti‐Xoom antibodies revealed that there are two forms of Xoom protein in Xenopus embryos: (i) a 45 kDa soluble cytoplasmic form; and (ii) a 44 kDa membrane‐associated form. Two forms of Xoom protein were ubiquitously detected from unfertilized egg to tadpole stage, with a qualitative peak during blastula and gastrula stages. Immunohistochemical examination showed that Xoom protein is maternally stored in the animal subcortical layer and divided into presumptive ectodermal cells during cleavage stages. Enzymatic digestion of membrane protein and immunologic detection of Xoom showed that Xoom exists as a membrane‐associated protein. To examine a function of Xoom protein, anti‐Xoom antibodies were injected into blastocoele of stage 7 blastula embryo. Anti‐Xoom antibodies caused gastrulation defect in a dose‐ dependent manner. These results suggest that maternally prepared Xoom protein is involved in gastrulation movement on ectodermal cells.

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Section: Discussionmentioning

confidence: 93%

Xoom is maternally stored and functions as a transmembrane protein for gastrulation movement in Xenopus embryos

2001

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“…This clone contained nucleotides 9-874 of a cDNA encoding the human homolog of Pleurodeles waltl RNA-associated protein, 55 kDa (RAP55; also known as LSm14) (Anantharaman and Aravind 2004;Khusial et al 2005). RAP55 was previously identified as a cytoplasmic, oocyte-specific protein in Pleurodeles (Lieb et al 1998). The cDNA encoding human RAP55 (NM_015578) predicts a 463-amino acid polypeptide with a molecular weight of 50.5 kDa.…”

Section: Resultsmentioning

confidence: 99%

“…Proteins that are homologous to human RAP55 exist in Caenorhabditis elegans (CAR-1) and Drosophila (Tra1), as well as Pleurodeles and Xenopus (Lieb et al 1998;Audhya et al 2005;Boag et al 2005). In these species, RAP55 expression is limited to germ cell development and early embryogenesis.…”

Section: Conservation Of Rap55 During Evolutionmentioning

confidence: 99%

RNA-associated protein 55 (RAP55) localizes to mRNA processing bodies and stress granules

Yang

Jiang²,

Gulick³

et al. 2006

RNA

150

136

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The mRNA processing body (P-body) is a cellular structure that has an important role in mRNA degradation. P-bodies have also been implicated in RNAi-mediated post-transcriptional gene silencing. The objective of this study was to identify and characterize novel components of the mammalian P-body. Approximately 5% of patients with the autoimmune disease primary biliary cirrhosis have antibodies directed against this structure. Serum from one of these patients was used to identify a cDNA encoding RAP55, a 463-amino acid protein. RAP55 colocalized with previously identified P-body components DCP1a and Ge-1. RAP55 contains an N-terminal Sm-like domain and two C-terminal RGG-rich domains separated by an FDF motif. The two RGG domains and the FDF domain were necessary and sufficient to target the protein to P-bodies. A fragment of RAP55 consisting of the FDF and the second RGG domains did not localize to P-bodies, but was able to displace other P-body components from this structure. After cells were subjected to arsenite-induced stress, RAP55 was detected in TIA-containing stress granules. The second RGG domain was necessary and sufficient for stress granule localization. siRNA-mediated knock-down of RAP55 resulted in loss of P-bodies, suggesting that RAP55 acts prior to the 5¢-decapping step in mRNA degradation. The results of this study show that RAP55 is a component of P-bodies in cells at rest and localizes in stress granules in arsenite-treated cells. RAP55 may serve to shuttle mRNAs between P-bodies and stress granules.

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“…RAP55 was originally identified in Pleurodeles oocytes (40). It was shown that the Pleurodeles RAP55 does not bind to mRNA directly using an oligo(dT)-based selection of UV-cross-linked lysates.…”

Section: Discussionmentioning

confidence: 99%

“…Among them, a protein of ϳ60 kDa was identified as a Xenopus homologue of RAP55. RAP55 was originally identified as an mRNA-associated protein of 55 kDa from newt Pleurodeles waltl oocytes (40). In this report, we focus on our analysis of the Xenopus RAP55 protein, which we hereafter refer to as "xRAP55."…”

Section: Identification Of the Components Of Frgy2-associatedmentioning

confidence: 99%

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

Tanaka

Ogawa

Takagi

et al. 2006

Journal of Biological Chemistry

106

128

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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.

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Identification of a Novel mRNA-Associated Protein in Oocytes ofPleurodeles waltlandXenopus laevis

Cited by 36 publications

References 37 publications

Xoom is maternally stored and functions as a transmembrane protein for gastrulation movement in Xenopus embryos

Xoom is maternally stored and functions as a transmembrane protein for gastrulation movement in Xenopus embryos

RNA-associated protein 55 (RAP55) localizes to mRNA processing bodies and stress granules

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

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