Riley Kasandra J-L, James Maher L
Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Biochem Biophys Res Commun. 2007 Nov 16;363(2):381-7. doi: 10.1016/j.bbrc.2007.08.181. Epub 2007 Sep 10.
Tumor suppressor p53 is a well-characterized transcription factor that binds DNA. More enigmatic are the RNA-binding properties of p53 and their physiological relevance. We used three sensitive co-immunoprecipitation methods in an attempt to detect RNAs that tightly associate with p53 in cultured human cells. Although recombinant p53 protein binds RNA in a sequence-nonspecific mode, we do not detect specific in vivo RNA binding by p53. These results suggest that RNA binding is prevented by post-translational p53 modifications. A ribonucleoprotein (not p53) is purified by multiple IgG monoclonal antibodies (including anti-p53 antibodies) from both p53 +/+ and p53 null cells. Caution is therefore required in interpreting RNA co-immunoprecipitation experiments. Though not formally excluded, these results do not support models in which p53 binds specific RNA partners in vivo.
肿瘤抑制因子p53是一种已被充分表征的能结合DNA的转录因子。p53的RNA结合特性及其生理相关性则更具神秘色彩。我们使用了三种灵敏的免疫共沉淀方法，试图检测在培养的人类细胞中与p53紧密结合的RNA。尽管重组p53蛋白以序列非特异性方式结合RNA，但我们并未检测到p53在体内的特异性RNA结合。这些结果表明，翻译后p53修饰可阻止RNA结合。通过多种IgG单克隆抗体（包括抗p53抗体）从p53 +/+和p53基因敲除细胞中纯化出一种核糖核蛋白（而非p53）。因此，在解释RNA免疫共沉淀实验时需谨慎。尽管未被正式排除，但这些结果并不支持p53在体内结合特定RNA伴侣的模型。
