Klevecz R R, Dowse H B
Department of Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
Cell Prolif. 2000 Aug;33(4):209-18. doi: 10.1046/j.1365-2184.2000.00171.x.
Image processing techniques and wavelet analyses have been applied to the yeast cell cycle expression microchip data to reveal large-scale temporally coherent structures and high frequency oscillations in mRNA levels through the cycle. Because transitions in expression frequently occur in phase, they appear as peaks or troughs in colour maps and contour plots of expression levels. Although apparent in the untreated data, these transitions were identified and enhanced by convolution of a Laplacian kernel with the expression arrays of the first 4096 genes. Transitions associated with maximum up- or down-regulation of mRNA levels appear as bands at 30-40 min intervals through two cell cycles. Time-frequency analyses using wavelet transforms support these visualization techniques and lead to the conclusion that, with respect to gene expression, the dominant period is not the cell cycle (90-120 min) but, more commonly, the higher frequency 30-40 minute submultiple of the cycle period.
图像处理技术和小波分析已应用于酵母细胞周期表达微芯片数据，以揭示整个周期中mRNA水平上大规模的时间相干结构和高频振荡。由于表达的转变经常在同一阶段发生，它们在表达水平的彩色图和等高线图中表现为峰值或谷值。虽然在未处理的数据中很明显，但通过将拉普拉斯核与前4096个基因的表达阵列进行卷积，这些转变被识别并增强了。与mRNA水平的最大上调或下调相关的转变在两个细胞周期中以30 - 40分钟的间隔呈现为条带。使用小波变换的时频分析支持了这些可视化技术，并得出结论，就基因表达而言，主导周期不是细胞周期（90 - 120分钟），而是更常见的周期的高频30 - 40分钟约数。
