title: Cell cycle dependent TN-C promoter activity determined by live cell imaging.
abstract: 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.
authors: Cell Systems Science Group/Biochemical Science Division, Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. michael.halter@nist.gov
authors: Michael
authors: M
authors: Halter
authors: Daniel R
authors: DR
authors: Sisan
authors: Joe
authors: J
authors: Chalfoun
authors: Benjamin L
authors: BL
authors: Stottrup
authors: Antonio
authors: A
authors: Cardone
authors: Alden A
authors: AA
authors: Dima
authors: Alessandro
authors: A
authors: Tona
authors: Anne L
authors: AL
authors: Plant
authors: John T
authors: JT
authors: Elliott
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics*; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D051379:Mice; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D041681:NIH 3T3 Cells; D011401:Promoter Regions, Genetic; D019063:Tenascin / Q000235:genetics* / Q000378:metabolism
chemical_list: D019063:Tenascin; D049452:Green Fluorescent Proteins