Protein synthesis in <i>Drosophila melanogaster</i> embryos

Mateu, Mauricio G.; Vicente, Óscar; Sierra, J M

doi:10.1111/j.1432-1033.1987.tb10564.x

Cited by 18 publications

(11 citation statements)

References 38 publications

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“…The identity of the band as eIF2␣ was confirmed by comparison with the positions of mammalian and D. melanogaster eIF2␣ (probed with antibodies specific for the respective proteins). This confirms the earlier finding that D. melanogaster eIF2␣ is a substrate for HRI (15). PKR was also able to phosphorylate eIF2␣ in extracts of Schneider cells (data not shown).…”

Section: Schneider Cell Extracts Display Eif2b Activity Which Issupporting

confidence: 81%

“…The affinity of eIF2 for GDP at physiological magnesium concentrations was such that a mechanism of catalysis would be required to form the active eIF2⅐GTP complex (13,14). However, Mateu and colleagues (13,15) reported that nucleotide exchange on D. melanogaster eIF2 was independent of an exchange factor under several conditions. Moreover, no guanine nucleotide exchange activity for eIF2 in D. melanogaster was detected in embryos (14).…”

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confidence: 99%

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Characterization of the Initiation Factor eIF2B and Its Regulation in Drosophila melanogaster

Williams¹,

Pavitt²,

Proud³

2001

Journal of Biological Chemistry

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Eukaryotic initiation factor (eIF) 2B catalyzes a key regulatory step in the initiation of mRNA translation. eIF2B is well characterized in mammals and in yeast, although little is known about it in other eukaryotes. eIF2B is a hetropentamer which mediates the exchange of GDP for GTP on eIF2. In mammals and yeast, its activity is regulated by phosphorylation of eIF2␣. Here we have cloned Drosophila melanogaster cDNAs encoding polypeptides showing substantial similarity to eIF2B subunits from yeast and mammals. They also exhibit the other conserved features of these proteins. D. melanogaster eIF2B␣ confers regulation of eIF2B function in yeast, while eIF2B⑀ shows guanine nucleotide exchange activity. In common with mammalian eIF2B⑀, D. melanogaster eIF2B⑀ is phosphorylated by glycogen synthase kinase-3 and casein kinase II. Phosphorylation of partially purified D. melanogaster eIF2B by glycogen synthase kinase-3 inhibits its activity. Extracts of D. melanogaster S2 Schneider cells display eIF2B activity, which is inhibited by phosphorylation of eIF2␣, showing the insect factor is regulated similarly to eIF2B from other species. In S2 cells, serum starvation increases eIF2␣ phosphorylation, which correlates with inhibition of eIF2B, and both effects are reversed by serum treatment. This shows that eIF2␣ phosphorylation and eIF2B activity are under dynamic regulation by serum. eIF2␣ phosphorylation is also increased by endoplasmic reticulum stress in S2 cells. These are the first data concerning the structure, function or control of eIF2B from D. melanogaster.

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Section: Schneider Cell Extracts Display Eif2b Activity Which Issupporting

confidence: 81%

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confidence: 99%

Characterization of the Initiation Factor eIF2B and Its Regulation in Drosophila melanogaster

Williams¹,

Pavitt²,

Proud³

2001

Journal of Biological Chemistry

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“…The total amount of this protein usually obtained from the postribosomal supernatant and the ribosomal highsalt wash of 100 g (wet weight) of embryos is about 180 ,ug. From this and the known values (25) of the mass of a wet embryo (20 ,ug) and the water space of an embryo (8 nl), a mean concentration of 130 nM can be inferred. Estimating a concentration of 80S ribosomes per embryo of about 1.8 ,uM (data not shown), we obtain a 35-kDa CBP-to-ribosome ratio of approximately 0.07.…”

Section: Discussionmentioning

confidence: 99%

“…However, to enable detailed study of mechanism of this control, the need to characterize the CBPs from this organism became evident (23). Such studies would also be of interest in elucidating the translational initiation mechanism in a eucaryote evolution-2182 MAROTO AND SIERRA ary distant from mammals, a goal we have already begun to pursue (24,25).…”

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confidence: 99%

Purification and characterization of mRNA cap-binding protein from Drosophila melanogaster embryos.

Maroto¹,

Sierra²

1989

Mol. Cell. Biol.

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A protein with specific affinity for the mRNA cap structure was purified both from the postribosomal supernatant and from the ribosomal high-salt wash of Drosophila melanogaster embryos by m7GTP-Sepharose However, in a cell-free system from Drosophila embryos, mRNA translation was specifically inhibited by these antibodies. The requirement of 35-kDa CBP for mRNA translation in Drosophila was diminished under ionic conditions in which the importance of mRNA cap structure recognition was reduced. Despite the structural differences between Drosophila 35-kDa CBP and mammalian initiation factor 4E, both proteins were functionally interchangeable in the in vitro translation system from Drosophia embryos.

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“…Drosophila eIF4E has been shown previously to be enriched in the post-ribosomal supernatant compared with ribosomal high salt wash (Maroto and Sierra, 1989). Post-ribosomal supernatants were prepared essentially as described previously (Mateu et al, 1987;Webster et al, 1991). Briefly, the * This work supported by a grant from the Medical Research Council of Canada (to P. L. and N. S.).…”

Section: Methodsmentioning

confidence: 99%

Alternatively Spliced Transcripts from the Gene Produce Two Different Cap-binding Proteins

Lavoie

Lachance

Sonenberg

et al. 1996

Journal of Biological Chemistry

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Eukaryotic initiation factor 4E (eIF4E) is the subunit of eIF4F that binds to the cap structure at the 5 end of messenger RNA and is a critical component for the regulation of translation initiation. Using 7-methyl-GTPSepharose affinity chromatography, two distinct capbinding proteins that migrate on SDS-polyacrylamide gel electrophoresis at approximately 35 kDa were purified from Drosophila adults. Peptide microsequence analysis indicated that these two proteins differ at their amino termini. Analysis of a set of cDNA clones encoding eIF4E led to the conclusion that the two different protein isoforms, which we term eIF4EI and eIF4EII, result from three alternatively spliced transcripts from a single eIF4E gene, which maps to region 67A8-B2 on polytene chromosomes. The three eIF4E transcripts also vary greatly in the lengths of their 5-UTRs, suggesting the possibility of complex translational control of expression of the two eIF4E isoforms.

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Protein synthesis in Drosophila melanogaster embryos

Cited by 18 publications

References 38 publications

Characterization of the Initiation Factor eIF2B and Its Regulation in Drosophila melanogaster

Characterization of the Initiation Factor eIF2B and Its Regulation in Drosophila melanogaster

Purification and characterization of mRNA cap-binding protein from Drosophila melanogaster embryos.

Alternatively Spliced Transcripts from the Gene Produce Two Different Cap-binding Proteins

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