TY - JOUR T1 - Cell cycle dependent TN-C promoter activity determined by live cell imaging. JF - Cytometry. Part A : the journal of the International Society for Analytical Cytology Y1 - 2011 A1 - Halter, Michael A1 - Sisan, Daniel R A1 - Chalfoun, Joe A1 - Stottrup, Benjamin L A1 - Cardone, Antonio A1 - Dima,Alden A. A1 - Tona, Alessandro A1 - Plant,Anne L. A1 - Elliott, John T KW - Animals KW - cell cycle KW - Gene Expression Regulation KW - Green Fluorescent Proteins KW - Image Processing, Computer-Assisted KW - Mice KW - Microscopy, Fluorescence KW - Microscopy, Phase-Contrast KW - NIH 3T3 Cells KW - Promoter Regions, Genetic KW - Tenascin AB - The extracellular matrix protein tenascin-C plays a critical role in development, wound healing, and cancer progression, but how it is controlled and how it exerts its physiological responses remain unclear. By quantifying the behavior of live cells with phase contrast and fluorescence microscopy, the dynamic regulation of TN-C promoter activity is examined. We employ an NIH 3T3 cell line stably transfected with the TN-C promoter ligated to the gene sequence for destabilized green fluorescent protein (GFP). Fully automated image analysis routines, validated by comparison with data derived from manual segmentation and tracking of single cells, are used to quantify changes in the cellular GFP in hundreds of individual cells throughout their cell cycle during live cell imaging experiments lasting 62 h. We find that individual cells vary substantially in their expression patterns over the cell cycle, but that on average TN-C promoter activity increases during the last 40% of the cell cycle. We also find that the increase in promoter activity is proportional to the activity earlier in the cell cycle. This work illustrates the application of live cell microscopy and automated image analysis of a promoter-driven GFP reporter cell line to identify subtle gene regulatory mechanisms that are difficult to uncover using population averaged measurements. VL - 79 CP - 3 U1 - http://www.ncbi.nlm.nih.gov/pubmed/22045641?dopt=Abstract M3 - 10.1002/cyto.a.21028 ER -