Dong Jinjiang, Akcakanat Argun, Stivers David N, Zhang Jiexin, Kim Doyil, Meric-Bernstam Funda
Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
RNA Biol. 2009 Jan-Mar;6(1):59-64. doi: 10.4161/rna.6.1.7458. Epub 2009 Jan 19.
Y-box protein 1 (YB-1) is a multifunctional DNA/RNA-binding protein that regulates transcription and translation. The specificity of YB-1's RNA binding and its consequences are unknown. Because expression and subcellular localization of YB-1 have been reported to be important in breast cancer, we determined the specificity and functional impact of YB-1 mRNA-binding in MCF7 breast cancer cells. We used YB-1 antibodies to immunoprecipitate YB-1 and microarray profiling to compare YB-1-bound and total poly(A) RNA. We demonstrated that YB-1 mRNA-binding was preferential. Transcript sequences significantly associated with this binding had high GC content. Selected YB-1 mRNA-binding targets were confirmed by QRT-PCR. However, downregulation of YB-1 levels by siRNA did not affect their RNA or protein expression. Thus, YB-1 has RNA-binding specificity; however, YB-1 binding does not necessarily regulate the stability or translation of its mRNA targets. Further study is needed to determine the functional consequences of selective YB-1 mRNA binding.
Y盒蛋白1（YB-1）是一种多功能DNA/RNA结合蛋白，可调节转录和翻译。YB-1与RNA结合的特异性及其后果尚不清楚。由于据报道YB-1的表达和亚细胞定位在乳腺癌中很重要，我们确定了YB-1在MCF7乳腺癌细胞中与mRNA结合的特异性和功能影响。我们使用YB-1抗体免疫沉淀YB-1，并通过微阵列分析比较与YB-1结合的和总的聚腺苷酸（poly(A)）RNA。我们证明YB-1与mRNA的结合具有偏好性。与这种结合显著相关的转录本序列具有高GC含量。通过实时定量聚合酶链反应（QRT-PCR）证实了选定的YB-1与mRNA结合的靶点。然而，小干扰RNA（siRNA）下调YB-1水平并不影响其RNA或蛋白质表达。因此，YB-1具有RNA结合特异性；然而，YB-1的结合不一定调节其mRNA靶点的稳定性或翻译。需要进一步研究以确定YB-1选择性结合mRNA的功能后果。
