Proportions of H1 histone subspecies in human fibroblasts shift during density-dependent growth arrest independent of replicative senescence.
H1 histone subspecies have been reported to vary during tissue differentiation, during aging of mammalian tissues, and as a function of DNA replicative activity. Since cultured human fibroblasts have a limited replicative life span which features arrest in the G1 phase of the cell cycle, we sought to distinguish whether any changes in the proportions of the principal H1 histone subspecies (H1A, H1B, and H1o) in late-passage fibroblasts were specific for senescent loss of replicative potential, or rather ensued as a result of prolonged inhibition of cell division. We observed an identical shift in the proportions of H1 histone subspecies during prolonged density-dependent inhibition of growth in both early-passage and late-passage cells. Since under these conditions there were no passage-specific changes, replicative senescence of human fibroblasts does not appear to involve a defect in the control of H1 histone proportions.
Houde
M
M
Department of Medicine, University of Arkansas for Medical Sciences, Little Rock.
Shmookler Reis
R J
RJ
Goldstein
S
S
D002453:Cell Cycle; D002470:Cell Survival; D002478:Cells, Cultured; D003260:Contact Inhibition; D005347:Fibroblasts / Q000502:physiology; D006657:Histones / Q000145:classification / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques
D006657:Histones