Fluorescence and NMR studies of intramolecular stacking of mRNA cap-analogues

Wieczorek, Z; Zdanowski, Konrad; Chlebicka, Lidia; Stępiński, Janusz; Jankowska, Marzena; Kierdaszuk, Borys; Temeriusz, Andrzej; Darżynkiewicz, Edward; Stolarski, Ryszard

doi:10.1016/s0167-4781(97)00116-4

Cited by 23 publications

(27 citation statements)

References 27 publications

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“…The structural modifications alter the conformer populations only slightly from those of natural dinucleotide caps Wieczorek et al 1997) and previously synthesized ARCAs (Stepinski et al 2001). Irrespective of the modifications in the m 7 Guo moiety, the populations of the Guo conformers in dynamic equilibrium are similar to one another (±5%) and close to the populations in 5Ј-GMP (Lassota et al 1984).…”

Section: Solution Conformations Of the Free Cap Analogsmentioning

confidence: 91%

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Novel “anti-reverse” cap analogs with superior translational properties

Jemielity

Fowler²,

Zuberek³

et al. 2003

RNA

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237

275

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Section: Solution Conformations Of the Free Cap Analogsmentioning

confidence: 91%

“…Numerical leastsquares nonlinear regression analysis was performed using ORGIN 6.0 from Microcal Software Inc. The population of the stacked cap analog was determined from the temperature dependence of the fluorescence intensity in phosphate buffer at pH 5.2 (Wieczorek et al 1997). …”

Section: Measurement Of Binding Affinity By Fluorescence Quenchingmentioning

confidence: 99%

Novel “anti-reverse” cap analogs with superior translational properties

Jemielity

Fowler²,

Zuberek³

et al. 2003

RNA

Self Cite

237

275

View full text Add to dashboard Cite

show abstract

“…They each contain an eight-stranded antiparallel ␤-sheet on top of three ␣-helices in a cupped-hand shape. Two Trp residues, located within a narrow cavity inside the concave surface, hold the guanine residue of the cap analogue through -stacking interaction (4,28,29,51), which is further stabilized by the hydrogen bonds among the purine base, the polypeptide backbone, and a conserved Glu residue. A third Trp residue recognizes the N7-methyl group of the cap structure, thus contributing to the specificity of cap binding (43).…”

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confidence: 99%

Identification in the Ancient Protist Giardia lamblia of Two Eukaryotic Translation Initiation Factor 4E Homologues with Distinctive Functions

Wang

2005

Eukaryot Cell

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Eukaryotic translation initiation factor 4E (eIF4E) binds to the m 7 GTP of capped mRNAs and is an essential component of the translational machinery that recruits the 40S small ribosomal subunit. We describe here the identification and characterization of two eIF4E homologues in an ancient protist, Giardia lamblia. Using m 7 GTP-Sepharose affinity column chromatography, a specific binding protein was isolated and identified as Giardia eIF4E2. The other homologue, Giardia eIF4E1, bound only to the m 2,2,7 GpppN structure. Although neither homologue can rescue the function of yeast eIF4E, a knockdown of eIF4E2 mRNA in Giardia by a virus-based antisense ribozyme decreased translation, which was shown to use m 7 GpppN-capped mRNA as a template. Thus, eIF4E2 is likely the cap-binding protein in a translation initiation complex. The same knockdown approach indicated that eIF4E1 is not required for translation in Giardia. Immunofluorescence assays showed wide distribution of both homologues in the cytoplasm. But eIF4E1 was also found concentrated and colocalized with the m 2,2,7 GpppN cap, 16S-like rRNA, and fibrillarin in the nucleolus-like structure in the nucleus. eIF4E1 depletion from Giardia did not affect mRNA splicing, but the protein was bound to Giardia small nuclear RNAs D and H known to have an m 2,2,7 GpppN cap, thus suggesting a novel function not yet observed among other eIF4Es in eukaryotes.Most eukaryotic mRNAs, small nuclear RNAs (snRNAs), and small nucleolar RNAs (snoRNAs) are modified posttranscriptionally in the nucleus at their 5Ј end by addition of a 7-methylguanosine (m 7 G) cap linked by a 5Ј-5Ј-triphosphate bridge to the first transcribed residue (11,45). The cap of snRNAs and snoRNAs is then further methylated at its N2 position in the cytoplasm or nucleus to yield an N2,N2,7-methylguanosine (m 2,2,7 G) cap (41). The m 7 GpppN-cap structure is required for recruitment of mRNA by the translational machinery, whereas the m 2,2,7 GpppN-cap plays crucial roles in gene expression, such as mRNA splicing, methylation, pseudouridylation, and rRNA processing and ribosome assembly (41).The m 7 GpppN-cap of mRNA is recognized by eukaryotic initiation factor 4E (eIF4E), which interacts also with scaffold protein eIF4G (13, 30). The latter binds to an ATP-dependent RNA helicase, eIF4A, and ribosome-bound eIF3 to recruit the 40S small ribosomal subunit to the 5Ј end of an mRNA for translation initiation (14,16,20,24). eIF4E is not only a translation initiation factor but also a protein that modulates the overall rate of translation and the mRNA selectivity of the translation apparatus (11, 13). The functional importance of eIF4E is illustrated by the lethality of eif4e gene disruption in Saccharomyces cerevisiae (3). Both the function and structure of eIF4E have been conserved throughout evolution; human and yeast homologues are 31% identical at the amino acid level, and human eIF4E can rescue eif4e gene disruption in S. cerevisiae (3). In spite of the variable N and C termini among the eIF4Es, a core of a...

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“…6,11) The interactions with m 7 GTP and m 7 GpppA were compared to determine the contribution of the second nucleotide of m 7 GpppA/G to the interaction with eIF4E. Their association constants were estimated from the respective slopes of Eadie-Hofstee plots (Fig.…”

Section: Resultsmentioning

confidence: 99%