利用不同方法检测RNAi抑制人pescadillo基因的表达

目的:构建人pescadillo(PES1)基因siRNA的真核表达载体,观察其对PES1表达的影响。方法:利用RNA干扰(RNAi)技术,设计并合成了2条针对PES1基因的siRNA,将其克隆到siRNA表达载体pSliencer2.1-U6neo上。分别用以下3种方法检测RNAi的抑制效果:(1)将RNAi重组质粒和带FLAG标签的PES1共转染293T人胚肾细胞,用FLAG抗体进行Western blot;(2)将RNAi重组质粒和带GFP标签的PES1共转染293T细胞,用荧光显微镜观察GFP的亮度;(3)在293T细胞中仅转染小干扰RNA(siRNA)重组质粒,用PES1抗体进行Western blot分析。结果:测序证明,成功构建了PES1siRNA真核表达载体。通过Western blot实验证明,构建的siRNA能有效抑制外源性及内源性PES1基因表达;荧光显微镜检查发现siRNA能明显减弱细胞中荧光强度,抑制PES1的表达。结论:成功地构建了PES1siRNA的真核表达载体,利用3种不同方法均证明该siRNA能有效地抑制PES1基因的表达。

人Pescadillo能够诱导大规模染色质伸展

人Pescadillo基因编码的蛋白分子中含有一个BRCT结构域,Pescadillo在DNA合成、细胞增殖和转化中发挥重要作用.考虑到BRCT结构域能够诱导大规模染色质伸展,对Pescadillo 在大规模染色质伸展中的作用进行了研究.首先从人乳腺MCF10A细胞中得到了Pescadillo编码区的cDNA,其序列在第580-582位氨基酸发生缺失,将该cDNA片段与lac阻遏物在AO3-1细胞中融合表达,通过lac阻遏物结合细胞基因组中含有lac操纵基因的区域将Pescadillo靶向至染色质周围,发现Pescadillo能够诱导大规模染色质伸展,并将诱导大规模染色质伸展活性的结构域定位至其BRCT结构域,这为深入理解Pescadillo的重要作用提供了新的线索.

Human pescadillo induces large-scale chromatin unfolding

The human pescadillo gene encodes a protein with a BRCT domain. Pescadillo plays an important role in DNA synthesis, cell proliferation and transformation. Since BRCT do- mains have been shown to induce chromatin large-scale unfolding, we tested the role of Pesca- dillo in regulation of large-scale chromatin unfolding. To this end, we isolated the coding region of Pescadillo from human mammary MCF10A cells. Compared with the reported sequence, the isolated Pescadillo contains in-frame deletion from amino acid 580 to 582. Targeting the Pesca- dillo to an amplified, lac operator-containing chromosome region in the mammalian genome re- sults in large-scale chromatin decondensation. This unfolding activity maps to the BRCT domain of Pescadillo. These data provide a new clue to understanding the vital role of Pescadillo.

The antibody preparation and expression of human Pescadillo

To explore the biological roles of human Pescadillo and investigate its potential effect on tumorigene- sis, the cDNA of Pescadillo was fused with that of GST. After purification and elution, the purified GST-Pescadillo fusion protein was obtained, and the antibody against the fusion protein was generated. Endogenous Pescadillo protein was observed to be remarkably induced by estrogen. It was mainly distributed in the tissues such as breast, ovary and intestine, all of which contain proliferating cells, and was also detected in many cell lines of human cancer: renal carcinoma, hepatoma, ovarian cancer, colon carcinoma, and breast cancer. The expression level of Pescadillo was increased significantly in breast cancer tissues compared with their paired margin tissues. Taken together, these data suggest that Pescadillo may play important roles in the initiation and development of cancer and may be a po- tential target in cancer diagnosis and therapy.

制备单克隆抗体检测PES1的表达

目的:制备PES1单克隆抗体(mAb)并用所制备的抗体检测PES1在多种肿瘤细胞中的表达及其在成年大鼠不同组织中的表达分布。方法:纯化GST-PES1(1-322aa)融合蛋白后注入小鼠进行免疫,经过细胞融合、筛选以及用Western blot进行特异性鉴定后获得mAb。再用制备的mAb检测PES1在不同的人肿瘤细胞和大鼠不同组织中的表达。结果:所制备的PES1 mAb能特异地识别PES1。用所制备的mAb检测发现,在所检测的人乳腺癌、卵巢癌、肝癌以及肺癌等细胞中均有不同程度的表达;PES1类似物pescadillo在大鼠的乳腺和卵巢组织中表达,但在其他组织中没有被检测到。结论:成功地制备了PES1的mAb。PES1可能与肿瘤的发生发展有一定的关系;由于PES1明显表达于雌激素重要的靶器官,所以可能参与雌激素信号通路。

沉默PES1基因表达对结肠癌细胞恶性表型的抑制作用

目的 :探讨核仁蛋白PES1(pescadillo homolog 1)对结肠癌细胞恶性表型的影响。方法 :构建针对PES1基因的sh RNA干扰质粒,将其转染结肠癌HCT116细胞,经G418筛选耐药细胞克隆,蛋白质印迹法验证靶基因的沉默效果。采用MTT法、平板克隆形成实验、裸鼠成瘤实验、Transwell迁移及侵袭实验和FCM法分别检测沉默PES1表达对HCT116细胞增殖、克隆形成、体内成瘤、体外迁移和侵袭以及凋亡的影响,并采用实时荧光定量PCR和蛋白质印迹法检测细胞增殖和凋亡相关蛋白的表达水平。结果 :成功获得PES1稳定低表达的结肠癌HCT116细胞。沉默PES1表达后,HCT116细胞的增殖、克隆形成和裸鼠体内成瘤能力均明显降低(P值均<0.01),细胞迁移和侵袭能力明显减弱(P值均<0.01),细胞凋亡水平明显提高(P<0.05)。PES1表达被抑制后,HCT116细胞中细胞周期蛋白D1(cyclin D1)和Bcl-2蛋白表达水平明显降低(P值均<0.01),而Bcl-2相互作用杀伤蛋白(Bcl-2 interacting killer,BIK)、prune同源蛋白2(prune homolog 2,PRUNE2)和基质金属蛋白酶组织抑制因子3(tissue inhibitor of matrix metalloproteinase 3,TIMP3)的m RNA表达水平明显升高(P值均<0.01)。结论 :PES1可能对结肠癌细胞的多种恶性表型起促进作用。