Brain Poly(A)RNA During Aging: Stability of Yield and Sequence Complexity in Two Rat Strains

Autor: P. D. Colman, B. B. Kaplan, Caleb E. Finch, Heinz H. Osterburg
Rok vydání: 1980
Předmět:
Zdroj: Journal of Neurochemistry. 34:335-345
ISSN: 1471-4159
0022-3042
Popis: To evaluate whether major age-related changes occur during aging in the brain, we determined the sequence complexity of total poly(A)RNA and polysomal poly(A)RNA of brains from Sprague-Dawley and Fischer 344 male rats, aged 2-32 months. RNA complexity, determined by RNA-driven hybridization reactions with nonrepetitive DNA, was 6-7 × 108 nucleotides for total poly(A)RNA, whereas polysomal poly(A)RNA had a sequence complexity of 2.3-2.8 × 108 nucleotides. Sprague-Dawley rats had polysomal poly(A)RNA with a yield per gram of brain and a complexity that was 20% greater than Fischer 344 rats. No age differences in total or polysomal poly(A)RNA complexity were detected in either strain. Mixtures of polysomal poly(A)RNA from different age groups gave complexity values that were indistinguishable from the complexity of each component, thereby indicating that most (>80%) of the RNA sequences are common to all age groups studied. Analysis of total poly(A)RNA hybridization kinetics indicated that the major kinetic component had similar pseudo-first-order rate constants and complexity in all age groups. Consideration of interassay variation suggests that the limits of age changes in poly(A)RNA sequence complexity or content are 10%. Thus, age changes may be smaller than interstrain differences in the rat. We conclude that if genomic function is grossly impaired during aging, as presumed in many contemporary theories, the impairments are not expressed in most brain cells.
Databáze: OpenAIRE
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