Mxi1 inhibits the proliferation of U87 glioma cells through down-regulation of cyclin B1 gene expression.
Bottom Line: This inhibition occurs at the transcriptional level and depends, at least in part, on the E-box present on the cyclin B1 promoter.Consistent with this, the endogenous Mxi1 binds this E-box in vitro.Thus, our findings indicate that Mxi1 can act as a tumour suppressor in human glioblastomas through a molecular mechanism involving the transcriptional down-regulation of cyclin B1 gene expression.
Affiliation: Istituto Regina Elena, Centro Ricerca Sperimentale, Laboratorio di Oncogenesi Molecolare, Via delle messi D'Oro 156, 00158 Rome, Italy.Show MeSH
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Mentions: To dissect the molecular mechanism through which Mxi1 induces accumulation in the G2/M phase of the cell cycle, we investigated, in U87 proliferating cells, the expression of cyclin B1 gene and of cyclin A as control. The level of the two cyclin mRNAs was evaluated by Northern blot on RNA of U87.Mxi1.14, U87.Mxi1.22 and U87 wild-type cells. MXI1 and beta-actin transcripts were also analyzed on the same membrane. Figure 5Figure 5
Affiliation: Istituto Regina Elena, Centro Ricerca Sperimentale, Laboratorio di Oncogenesi Molecolare, Via delle messi D'Oro 156, 00158 Rome, Italy.