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Purification and characterization of a protein associated with genetically-determined longevity difference in
A Okano1, I Yonemura, Y Shimizu
1Department of Lipid Biochemistry, Shinshu University School of Medicine, Matsumoto, Japan.
Abstract:
Earlier studies have shown a correlation between the presence of a 77 kDa protein in the proteins extracted from young adult Drosophila melanogaster (D.m.) and the autosomal longevity allele. A2 at the JmA locus. In this study, a 77 kDa protein has been isolated from pupae of D.m. of a long-lived strain of genotype A2A2, and was purified by DEAE chromatography, ConA column chromatography, and two cycles of gel filtration. The purified protein has a molecular weight of 76,600 (by SDS-PAGE), an isoelectric point of pH 6.5, and molar extinction coefficient A(280(1%) = 18.3. It is a glycoprotein containing 3.3% hexose. Supplementing the food of D.m. with the purified protein at 5 x 10(-4) micrograms/ml, beginning at day 5 after emergence, resulted in an increase in the survival rate and maximal life span of both short-lived and long-lived strains of D.m.
Insights
A purified 77 kDa glycoprotein from Drosophila melanogaster extends lifespan. Supplementing fruit fly food with this protein increased survival rates in both short-lived and long-lived strains.
Area of Science:
- Molecular Biology
- Genetics
- Gerontology
Background:
- A 77 kDa protein in Drosophila melanogaster (D.m.) is correlated with the autosomal longevity allele A2 at the JmA locus.
- Previous research indicates a link between this specific protein and extended lifespan in fruit flies.
Purpose of the Study:
- To isolate and characterize the 77 kDa protein associated with longevity in D.m.
- To investigate the effect of this purified protein on the survival rate and lifespan of D.m.
Main Methods:
- Isolation of the 77 kDa protein from pupae of a long-lived D.m. strain (A2A2 genotype).
- Purification using DEAE chromatography, ConA column chromatography, and gel filtration.
- Characterization including SDS-PAGE, isoelectric focusing, and hexose content analysis.
- Supplementation of D.m. food with the purified protein to assess lifespan effects.
Main Results:
- A 77 kDa glycoprotein was successfully isolated and purified.
- The purified protein has a molecular weight of 76,600 Da, an isoelectric point of pH 6.5, and contains 3.3% hexose.
- Supplementation with the protein (5 x 10(-4) µg/ml) increased survival rate and maximal lifespan in both short-lived and long-lived D.m. strains.
Conclusions:
- The isolated 77 kDa glycoprotein plays a role in modulating lifespan in Drosophila melanogaster.
- Dietary supplementation with this longevity-associated protein can enhance survival and extend the maximum lifespan of fruit flies.