scholarly journals Determinants of Initiation Codon Selection during Translation in Mammalian Cells

PLoS ONE ◽  
2010 ◽  
Vol 5 (11) ◽  
pp. e15057 ◽  
Author(s):  
Daiki Matsuda ◽  
Vincent P. Mauro
Keyword(s):  
Mammalian Cells ◽  
Initiation Codon ◽  
Codon Selection

scholarly journals The Role of eIF1 in Translation Initiation Codon Selection in Caenorhabditiselegans

Genetics ◽  
2010 ◽  
Vol 186 (4) ◽  
pp. 1187-1196 ◽  
Author(s):  
Lisa L. Maduzia ◽  
Anais Moreau ◽  
Nausicaa Poullet ◽  
Sebastien Chaffre ◽  
Yinhua Zhang
Keyword(s):  
Translation Initiation ◽  
Initiation Codon ◽  
Translation Initiation Codon ◽  
Codon Selection

Effect of upstream reading frames on translation efficiency in simian virus 40 recombinants

1986 ◽  
Vol 6 (7) ◽  
pp. 2704-2711 ◽  
Author(s):  
D S Peabody ◽  
S Subramani ◽  
P Berg
Keyword(s):  
Mammalian Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Initiation Codon ◽  
Efficient Production ◽  
Translation Efficiency ◽  
Reading Frame ◽  
Recombinant Viruses ◽  
Internal Translation ◽  
Late Region

In a previous report (S. Subramani, R. Mulligan, and P. Berg, Mol. Cell. Biol. 1:854-864, 1981), it was shown that mouse dihydrofolate reductase (DHFR) could be efficiently expressed from simian virus 40 recombinant viruses containing the DHFR cDNA in different locations in the viral late region. This was true even in the case of the SVGT7dhfr26 recombinant, which had the DHFR coding sequence 700 to 800 nucleotides from the 5' end of the mRNA, where it was preceded by the VP2 and VP3 initiator AUGs and a number of other noninitiator AUGs. To investigate the process of internal translation initiation in mammalian cells, we constructed a series of SVGT7dhfr recombinants in which the upstream VP2 and VP3 reading frame was terminated in various positions relative to the DHFR initiation codon. The efficient production of DHFR in infected CV1 cells depended on having the terminators of the VP2-VP3 reading frame positioned upstream or nearby downstream from the DHFR initiation codon. These results reinforce the notion that mammalian ribosomes are capable of translational reinitiation.

Multiple isoforms of the translation initiation factor eIF4GII are generated via use of alternative promoters, splice sites and a non-canonical initiation codon

2012 ◽  
Vol 448 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Mark J. Coldwell ◽  
Ulrike Sack ◽  
Joanne L. Cowan ◽  
Rachel M. Barrett ◽  
Markete Vlasak ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Ribosomal Subunit ◽  
Mrna Translation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Initiation Codon ◽  
Alternative Promoters ◽  
Multiple Promoters ◽  
N Terminus ◽  
Eukaryotic Initiation Factor 4G

During the initiation stage of eukaryotic mRNA translation, the eIF4G (eukaryotic initiation factor 4G) proteins act as an aggregation point for recruiting the small ribosomal subunit to an mRNA. We previously used RNAi (RNA interference) to reduce expression of endogenous eIF4GI proteins, resulting in reduced protein synthesis rates and alterations in the morphology of cells. Expression of EIF4G1 cDNAs, encoding different isoforms (f–a) which arise through selection of alternative initiation codons, rescued translation to different extents. Furthermore, overexpression of the eIF4GII paralogue in the eIF4GI-knockdown background was unable to restore translation to the same extent as eIF4GIf/e isoforms, suggesting that translation events governed by this protein are different. In the present study we show that multiple isoforms of eIF4GII exist in mammalian cells, arising from multiple promoters and alternative splicing events, and have identified a non-canonical CUG initiation codon which extends the eIF4GII N-terminus. We further show that the rescue of translation in eIF4GI/eIF4GII double-knockdown cells by our novel isoforms of eIF4GII is as robust as that observed with either eIF4GIf or eIF4GIe, and more than that observed with the original eIF4GII. As the novel eIF4GII sequence diverges from eIF4GI, these data suggest that the eIF4GII N-terminus plays an alternative role in initiation factor assembly.

ABC50 mutants modify translation start codon selection

2015 ◽  
Vol 467 (2) ◽  
pp. 217-229 ◽  
Author(s):  
Joanna D. Stewart ◽  
Joanne L. Cowan ◽  
Lisa S. Perry ◽  
Mark J. Coldwell ◽  
Christopher G. Proud
Keyword(s):  
Site Selection ◽  
Initiation Factor ◽  
Start Codon ◽  
Initiation Codon ◽  
Start Site ◽  
Key Factors ◽  
Initiation Factors ◽  
Translation Start ◽  
Initiation Factor 2 ◽  
Codon Selection

ATP-binding cassette 50 (ABC50; also known as ABCF1) binds to eukaryotic initiation factor 2 (eIF2) and is required for efficient translation initiation. An essential step of this process is accurate recognition and selection of the initiation codon. It is widely accepted that the presence and movement of eIF1, eIF1A and eIF5 are key factors in modulating the stringency of start-site selection, which normally requires an AUG codon in an appropriate sequence context. In the present study, we show that expression of ABC50 mutants, which cannot hydrolyse ATP, decreases general translation and relaxes the discrimination against the use of non-AUG codons at translation start sites. These mutants do not appear to alter the association of key initiation factors to 40S subunits. The stringency of start-site selection can be restored through overexpression of eIF1, consistent with the role of that factor in enhancing stringency. The present study indicates that interfering with the function of ABC50 influences the accuracy of initiation codon selection.

scholarly journals Effect of upstream reading frames on translation efficiency in simian virus 40 recombinants.

1986 ◽  
Vol 6 (7) ◽  
pp. 2704-2711 ◽  
Author(s):  
D S Peabody ◽  
S Subramani ◽  
P Berg
Keyword(s):  
Mammalian Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Initiation Codon ◽  
Efficient Production ◽  
Translation Efficiency ◽  
Reading Frame ◽  
Recombinant Viruses ◽  
Internal Translation ◽  
Late Region

In a previous report (S. Subramani, R. Mulligan, and P. Berg, Mol. Cell. Biol. 1:854-864, 1981), it was shown that mouse dihydrofolate reductase (DHFR) could be efficiently expressed from simian virus 40 recombinant viruses containing the DHFR cDNA in different locations in the viral late region. This was true even in the case of the SVGT7dhfr26 recombinant, which had the DHFR coding sequence 700 to 800 nucleotides from the 5' end of the mRNA, where it was preceded by the VP2 and VP3 initiator AUGs and a number of other noninitiator AUGs. To investigate the process of internal translation initiation in mammalian cells, we constructed a series of SVGT7dhfr recombinants in which the upstream VP2 and VP3 reading frame was terminated in various positions relative to the DHFR initiation codon. The efficient production of DHFR in infected CV1 cells depended on having the terminators of the VP2-VP3 reading frame positioned upstream or nearby downstream from the DHFR initiation codon. These results reinforce the notion that mammalian ribosomes are capable of translational reinitiation.

Ultrastructural Alterations in Hela Cells Induced by Spider Venom

1967 ◽  
Vol 25 ◽  
pp. 20-21
Author(s):  
Dale E. McClendon ◽  
Paul N. Morgan ◽  
Bernard L. Soloff
Keyword(s):  
Growth Medium ◽  
Mammalian Cells ◽  
Carcinoma Cells ◽  
Venom Protein ◽  
Sterile Saline ◽  
Carbon Coated ◽  
Available Information ◽  
Loxosceles Reclusa ◽  
Essential Growth ◽  
Solution Cultures

It has been observed that minute amounts of venom from the brown recluse spider, Loxosceles reclusa, are capable of producing cytotoxic changes in cultures of certain mammalian cells (Morgan and Felton, 1965). Since there is little available information concerning the effect of venoms on susceptible cells, we have attempted to characterize, at the electron microscope level, the cytotoxic changes produced by the venom of this spider.Cultures of human epithelial carcinoma cells, strain HeLa, were initiated on sterile, carbon coated coverslips contained in Leighton tubes. Each culture was seeded with approximately 1x105 cells contained in 1.5 ml of a modified Eagle's minimum essential growth medium prepared in Hank's balanced salt solution. Cultures were incubated at 36° C. for three days prior to the addition of venom. The venom was collected from female brown recluse spiders and diluted in sterile saline. Protein determinations on the venom-were made according to the spectrophotometric method of Waddell (1956). Approximately 10 μg venom protein per ml of fresh medium was added to each culture after discarding the old growth medium. Control cultures were treated similarly, except that no venom was added. All cultures were reincubated at 36° C.

Use of Uranium-Labeled Antibodies for Electron Microscopic Localization of Various Antigens in Mammalian Cells

1967 ◽  
Vol 25 ◽  
pp. 136-137
Author(s):  
J. P. Petrali ◽  
E. J. Donati ◽  
L. A. Sternberger
Keyword(s):  
Endoplasmic Reticulum ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Specific Antiserum ◽  
Electron Microscopic ◽  
E Coli ◽  
Cytoplasmic Membranes ◽  
Viral Progeny ◽  
Ultrathin Sections ◽  
Electron Microscopic Localization

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.

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