Effects of growth state and /sup 3/H labeling level on RNA turnover in WI-38 fibroblasts and HeLa cells

Journal Article · Sun Nov 01 04:00:00 EST 1981 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575665· OSTI ID:5822854

Sameshima, M; Schlessinger, D

The rate of turnover of prelabeled RNA in WI-38 human diploid fibroblasts varied with the level of /sup 3/H incorporated, the cell density of cultures, and the arrest of growth by senescence. The half-life of RNA in sparse cultures of growing WI-38 diploid fibroblasts depended on the level of (/sup 3/H)uridine incorporated; extrapolated to zero levels of incorporation, the half-life was 15 to 20 days. At any level of incorporated (/sup 3/H)uridine, however, RNA half-life decreased to 4 to 5 days in superconfluent cultures as the culture growth slowed. A similar shortening of half-life was observed when growth was stopped by /sup 3/H irradiation or clonal senescence. However, the rate of turnover was not simply dependent on whether cells were growing; for example, turnover did not increase when growth was arrested by incubating cells in conditioned medium. HeLa and L cells also showed an RNA half-life of about 14 to 20 days with an increase in turnover rate of crowded cultures. However, this increase occurred at higher cell densities than with the diploid fibroblasts. Also, the growth rate and rate of RNA turnover of HeLa and L cells were much less affected by incorporated /sup 3/H. The differential responses to confluence and /sup 3/H label can explain the higher turnover rate of RNA in normal human fibroblasts compared to SV40-transformed cells (S.A. Liebhaber, S. Wolf, and D. Schlessinger, Cell 13, 121-127 (1978)).

• Research Organization: Washington Univ. School of Medicine, St. Louis, MO
• OSTI ID: 5822854
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 88:2; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

550301* -- Cytology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
AZINES
BIOCHEMISTRY
BIOLOGICAL HALF-LIFE
CHEMISTRY
CONNECTIVE TISSUE CELLS
FIBROBLASTS
GROWTH
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
LABELLED COMPOUNDS
LABELLING
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RIBOSIDES
RNA
SOMATIC CELLS
TRITIUM COMPOUNDS
URACILS
URIDINE