抑癌基因p53的单细胞傅里叶变换显微红外光谱

Tumor Suppressor Gene p53 of Single Cell Fourier Transform Infrared Microspecroscopy

为探索单细胞红外光谱技术对单基因差异的鉴别能力,利用同步辐射傅里叶变换红外显微光谱技术采集含抑癌基因p53(野生型)和敲除抑癌基因p53(敲除型)结肠癌细胞的单细胞显微红外光谱。研究分析光谱发现,二者在脂质、蛋白质以及核酸吸收谱带峰强度和位置都有明显的差异。敲除p53后脂质、核酸以及蛋白特征吸收峰均减弱,且几乎所有的吸收峰都向高波数位移。分析了酰胺I带与酰胺II带的相对吸收强度比,发现敲除型比值明显变大;酰胺I带拟合结果表明野生型细胞中蛋白质二级结构的α螺旋和无规则卷曲含量明显低于敲除型,转角和非典型螺旋的含量则高于敲除型,而β折叠的含量无明显变化。研究表明,同步辐射单细胞红外光谱可以在分子水平上鉴别因p53基因差异而产生的细胞代谢变化。

In order to explore the capability of Fourier transform infrared microspecroscopy in discriminating single gene difference in single cell, synchrotron Fourier transform infrared microspecroscopy is used to measure single cell spectra of colorectal cancer cells with and without tumor suppressor gene p53, respectively. With comparison of spectra of these two types of cancer ceils, absorption intensities and frequencies of lipids, proteins and nucleic acids are evidently different. The absorption bands of single cell without p53 are weak and almost all the peaks drift to higher wavenumbers. Absorption intensity ratio of amide I/amide II increases significantly in the cell without p53, indicating the secondary structures of proteins change. The fitting analysis of amide I absorption band reveals that contents of a helix and random coil in secondary structures of proteins in cell with p53 gene are lower than that in cell without p53, and contents of turns and atypical helix are higher in cell with p53. However, content of/？-sheet in both cell is very similar. The results demonstrate that the absence of single gene p53 can affect metabolism activity, which can be clarified by synchrotron Fourier transform infrared microspecroscopy at molecular level.