Identification of okadaic-acid-induced genes by mRNA differential display in glioma cells

To identify novel genes associated with apoptosis in glioma cells, we treated T98G glioma cells with okadaic acid (OA). Differential display using 15 random primers was performed on RNA extracted from these cells. Upregulated bands were excised from polyacrylamide gels and cloned. Northern blots were used to confirm RNA expression in T98G cells. 18 RNA fragments corresponding to the untranslated region of genes were identified and sequenced. Three unknown gene fragments were used to screen a fetal brain cDNA library resulting in three complete cDNA sequences. The three sequences corresponded to a human gene homologous to the yeast translation initiation factor Sui-1, a cAMP-regulated phosphoprotein, ARPP-16/19, and a novel gene designated O48. Transcription of Sui-1 increased in response to all stress factors tested, whereas ARPP only responded to OA. 2-kb and 4-kb O48 RNA species were identified. OA and stress factors increased 2-kb expression while K252a (protein kinase inhibitor) increased 4-kb expression. Differential display is effective for identifying genes associated with apoptosis. Novel genes may be identified by further analysis of the gene fragments identified in this study. The function of O48 is unknown.