Parallel changes in protein synthesis and messenger RNA content in growing and resting epithelial cells of Xenopus laevis
✍ Scribed by Nancy E. Budorick; Leo Miller
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 851 KB
- Volume
- 111
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Abstract
The regulation of cell growth can be achieved at many levels but ultimately the regulatory factors must alter protein synthesis since growing cells always exhibit an increased rate of protein synthesis compared to resting cells. Some studies using growing and nongrowing mammalian cells have shown that the rate of protein synthesis compared to resting cells. Some studies using growing and nongrowing mammalian cells have shown that the rate of protein synthesis is directly dependent on mRNA content. Other studies have shown that growing and resting cells have similar amounts of mRNA and that protein synthesis is regulated by the proportion of mRNA in polysomes. We have analyzed mRNA content in growing and resting epithelial cells of Xenopus laevis. Quantitation of poly(A)^+^ mRNA by uniform labeling with ^3^H‐uridine and by ^3^H‐poly(U)hybridization demonstrated a direct relationship between mRNA content and the relative rate of protein synthesis in growing and resting cells. Likewise, after serum stimulation of resting cells the increase in mRNA content closely paralleled the increase in protein synthesis. Our results suggest that control of protein synthesis in growing and nongrowing cells is exerted before the translational level.