A longitudinal study of human age-related ribosomal RNA gene activity as detected by silver-stained NORs.
The relative frequencies of silver-stained nucleolar organizing regions (Ag-NORs) as a function of age have been analyzed in skin fibroblasts derived from eight adult individuals participating in the Gerontology Research Center (GRO) Longitudinal Study, NIA, Baltimore, MD. Since silver staining of NORs is correlated with rRNA gene activity, we used this cytological method to examine the pattern of rRNA gene activity in specific individuals, each at two different ages. Our results show that the average number of Ag-NORs/cell decreases significantly with advancing age of each individual, presumably indicating a general pattern of age-related decline/alteration in rRNA gene activity and this pattern is individual-specific. The findings of our longitudinal study is consistent with the results of previous cross-sectional (population) studies on rRNA gene activity as detected by Ag-NORs. However, it appears that the relative rate in the age-related decline of rRNA gene activity, as evidenced by lower Ag-NOR frequencies with age, is variable from person to person.
Thomas
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Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA.
Mukherjee
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics* / Q000473:pathology; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006801:Humans; D007621:Karyotyping; D008136:Longevity / Q000235:genetics; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009697:Nucleolus Organizer Region / Q000737:chemistry*; D012335:RNA, Ribosomal / Q000235:genetics*; D016622:Silver Staining; D012867:Skin / Q000648:ultrastructure*
D012335:RNA, Ribosomal