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Perspectives
Feedback Regulation of c-Myc by Ribosomal Protein L11
Mu-Shui Dai, Rosalie Sears and Hua Lu
volume 6 | issue 22
15 November 2007Pages: 2735 - 2741
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Several ribosomal proteins including L11 have been shown to activate p53 by inhibiting oncoprotein MDM2, leading to inhibition of cell cycle progression. Our recent study showed that L11 also inhibits oncoprotein c-Myc. Overexpression of L11 inhibits c-Myc-induced transcription and cell proliferation, while reduction of endogenous L11 increases these c-Myc activities. Interestingly, L11 is a transcriptional target of c-Myc, thus forming a negative feedback loop. We further showed that L11 competes with co-activator TRRAP for binding to c-Myc through the Myc box II (MB II) and reduces histone H4 acetylation at c-Myc target gene promoters. In addition, L11 appears to regulate c-Myc levels. Knocking down L11 markedly increases the mRNA and protein levels of endogenous c-Myc. These results suggest that L11 also inhibits cell cycle progression by regulating the c-Myc pathway. Here we further discuss the implications of this regulation and questions that this finding raises.
Authors
Mu-Shui Dai
Indiana University School of Medicine; Indianapolis, IN
Rosalie Sears
Oregon Health and Science University; Portland, OR
Hua Lu
Indiana University School of Medicine; Indianapolis, IN









