Differential Gene Expression in Apoptosis: Identification of Ribosomal Protein 23K, a Cell Proliferation Inhibitor
| Autor: | Yiannis A. Ioannou, Fannie W. Chen, Joanna P. Davies |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Ribosomal Proteins
Endocrinology Diabetes and Metabolism Molecular Sequence Data Gene Expression Apoptosis Biology Biochemistry Mice Endocrinology Ribosomal protein Complementary DNA Gene expression Tumor Cells Cultured Genetics Animals Humans Northern blot Cloning Molecular Molecular Biology DNA Primers Messenger RNA Differential display Base Sequence Cell growth Transfection Molecular biology Rats Up-Regulation Cell biology COS Cells Camptothecin Cell Division Subcellular Fractions |
| Zdroj: | Molecular Genetics and Metabolism. 64:271-282 |
| ISSN: | 1096-7192 |
| Popis: | Gene expression during the camptothecin-induced apoptotic death of human leukemic U937 cells and mouse T-cell hybridoma QW4.1 cells was studied by the mRNA differential display technique. Ten clones were confirmed to be differentially expressed, nine of which encoded novel sequences. One clone, U3.2, was induced approximately 10-fold in camptothecin-treated cells and was found to be identical to a highly basic 23-kDa human protein which contains basic leucine zipper-like motifs and has recently been identified as the human homologue of the rat ribosomal protein L13a. Northern blot analysis revealed a major mRNA of approximately 0.9 kb and a minor mRNA of approximately 1.3 kb. Overexpression of a full-length 23K cDNA, tagged with a FLAG sequence, in COS-7 cells revealed a predominantly nucleolar localization and the absence of any 23K protein from the cytoplasm. Subsequent transfection studies, using antisense phosphorothioate-modified oligonucleotides, revealed that inhibition of 23K expression results in an increased cell proliferation and greater sensitivity of U937 cells to the effects of camptothecin-induced cell death. Upregulation of 23K expression using a cDNA construct resulted in a decrease in cell proliferation and growth arrest, suggesting a role for 23K protein as a proliferation checkpoint following a cellular insult. |
| Databáze: | OpenAIRE |
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