Journal article
Regulation of Ribosomal Protein mRNA Content and Translation in Growth-Stimulated Mouse Fibroblasts
Molecular and cellular biology, Vol.2(6), pp.685-693
06/1982
DOI: 10.1128/MCB.2.6.685
PMCID: PMC369844
PMID: 14582163
Abstract
When resting (G0) mouse 3T6 fibroblasts are serum stimulated to reenter the cell cycle, the rates of synthesis of rRNA and ribosomal proteins increase, resulting in an increase in ribosome content beginning about 6 h after stimulation. In this study, we monitored the content, metabolism, and translation of ribosomal protein mRNA (rp mRNA) in resting, exponentially growing, and serum-stimulated 3T6 cells. Cloned cDNAs for seven rp mRNAs were used in DNA-excess filter hybridization studies to assay rp mRNA. We found that about 85% of rp mRNA is polyadenylated under all growth conditions. The rate of labeling of rp mRNA relative to total polyadenylated mRNA changed very little after stimulation. The half-life of rp mRNA was about 11 h in resting cells and about 8 h in exponentially growing cells, values which are similar to the half-lives of total mRNA in resting and growing cells (about 9 h). The content of rp mRNA relative to total mRNA was about the same in resting and growing 3T6 cells. Furthermore, the total amount of rp mRNA did not begin to increase until about 6 h after stimulation. Since an increase in rp mRNA content did not appear to be responsible for the increase in ribosomal protein synthesis, we determined the efficiency of translation of rp mRNA under different conditions. We found that about 85% of pulse-labeled rp mRNA was associated with polysomes in exponentially growing cells. In resting cells, however, only about half was associated with polysomes, and about 30% was found in the monosomal fraction. The distribution shifted to that found in growing cells within 3 h after serum stimulation. Similar results were obtained when cells were labeled for 10.5 h. About 70% of total polyadenylated mRNA was in the polysome fraction in all growth states regardless of labeling time, indicating that the shift in mRNA distribution was species specific. These results indicate that the content and metabolism of rp mRNA do not change significantly after growth stimulation. The rate of ribosomal protein synthesis appears to be controlled during the resting-growing transition by an alteration of the efficiency of translation of rp mRNA, possibly at the level of protein synthesis initiation.
Details
- Title: Subtitle
- Regulation of Ribosomal Protein mRNA Content and Translation in Growth-Stimulated Mouse Fibroblasts
- Creators
- Pamela K Geyer - Department of Biochemistry, The Ohio State University, Columbus, Ohio 43210Oded Meyuhas - The Institute for Cancer Research, Philadelphia, Pennsylvania 19111Robert P Perry - The Institute for Cancer Research, Philadelphia, Pennsylvania 19111Lee F Johnson - Department of Biochemistry, The Ohio State University, Columbus, Ohio 43210
- Resource Type
- Journal article
- Publication Details
- Molecular and cellular biology, Vol.2(6), pp.685-693
- DOI
- 10.1128/MCB.2.6.685
- PMID
- 14582163
- PMCID
- PMC369844
- NLM abbreviation
- Mol Cell Biol
- ISSN
- 0270-7306
- eISSN
- 1098-5549
- Language
- English
- Date published
- 06/1982
- Academic Unit
- Obstetrics and Gynecology; Biochemistry and Molecular Biology
- Record Identifier
- 9984024533102771
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