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Characterization of elongation factor-1A (eEF1A-1) and eEF1A-2/S1 protein expression in normal and wasted mice
A Khalyfa1, D Bourbeau, E Chen
1Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, The Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Québec H3T 1E2, Canada.
The Journal of Biological Chemistry
|April 11, 2001
Summary
The eEF1Alpha-2 gene provides the adult peptide elongation factor in brain and muscle, replacing the embryonic eEF1A-1 form. Its absence in mutant mice leads to neurodegeneration and muscle wasting, causing early fatality.
Area of Science:
- Molecular Biology
- Genetics
- Developmental Biology
Background:
- The eEF1Alpha-2 gene encodes a tissue-specific isoform of peptide elongation factor-1A (eEF1A-1), crucial for protein synthesis.
- This isoform is primarily expressed in the brain, heart, and skeletal muscle, tissues characterized by terminally differentiated cells.
- Homozygous mutant mice lacking functional eEF1Alpha-2 exhibit severe neurodegeneration and muscle wasting, leading to premature death.
Purpose of the Study:
- To investigate the developmental expression patterns of eEF1A-1 and eEF1A-2/S1 isoforms in wild-type, heterozygous, and homozygous mutant mice.
- To characterize the specific roles of eEF1A-1 and eEF1A-2/S1 during postnatal development in key tissues.
- To elucidate the molecular basis for the observed defects in eEF1Alpha-2 mutant mice.
Main Methods:
- Generation of a specific peptide-derived antiserum for the eEF1Alpha-2/S1 isoform, ensuring no cross-reactivity with eEF1A-1.
- Characterization of eEF1A-1 and eEF1A-2/S1 protein expression profiles during postnatal development using Western blotting or similar techniques.
- Analysis of isoform localization within specific cell types (neurons vs. non-neuronal cells) in the brain of adult wild-type mice.
Main Results:
- In wild-type and heterozygous mice, eEF1A-2/S1 expression begins postnatally in brain, heart, and muscle, coinciding with a decrease in eEF1A-1 levels.
- In homozygous mutants, eEF1A-2/S1 is absent, but eEF1A-1 levels decrease on schedule during development.
- In adult wild-type brains, eEF1A-2/S1 localizes to neurons, while eEF1A-1 is found in non-neuronal cells; eEF1A-1 is replaced by eEF1A-2/S1 in neurons by postnatal day 14.
Conclusions:
- eEF1A-2/S1 functions as the predominant adult isoform of peptide elongation factor-1A in the brain, heart, and skeletal muscle.
- eEF1A-1 serves as the embryonic isoform, with its expression declining as eEF1A-2/S1 becomes dominant postnatally.
- The absence of eEF1A-2/S1 and the developmental decline of eEF1A-1 in mutant mice likely impair protein synthesis, leading to severe developmental defects and lethality.
Keywords:
Non-programmatic