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Updated: May 19, 2026
Xenopus laevis as a Model to Identify Translation Impairment
Published on: September 27, 2015
Diphthamide modification on eukaryotic elongation factor 2 is needed to assure fidelity of mRNA translation and mouse
Shihui Liu1, Christopher Bachran, Pradeep Gupta
1Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. shliu@niaid.nih.gov
Abstract:
To study the role of the diphthamide modification on eukaryotic elongation factor 2 (eEF2), we generated an eEF2 Gly(717)Arg mutant mouse, in which the first step of diphthamide biosynthesis is prevented. Interestingly, the Gly(717)-to-Arg mutation partially compensates the eEF2 functional loss resulting from diphthamide deficiency, possibly because the added +1 charge compensates for the loss of the +1 charge on diphthamide. Therefore, in contrast to mouse embryonic fibroblasts (MEFs) from OVCA1(-/-) mice, eEF2(G717R/G717R) MEFs retain full activity in polypeptide elongation and have normal growth rates. Furthermore, eEF2(G717R/G717R) mice showed milder phenotypes than OVCA1(-/-) mice (which are 100% embryonic lethal) and a small fraction survived to adulthood without obvious abnormalities. Moreover, eEF2(G717R/G717R)/OVCA1(-/-) double mutant mice displayed the milder phenotypes of the eEF2(G717R/G717R) mice, suggesting that the embryonic lethality of OVCA1(-/-) mice is due to diphthamide deficiency. We confirmed that the diphthamide modification is essential for eEF2 to prevent -1 frameshifting during translation and show that the Gly(717)-to-Arg mutation cannot rescue this defect.
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