17 June 2011
Mike White
Faculty of Life Sciences
University of Manchester, UK
In the past 20 years there have been dramatic developments in our ability to observe and measure biological processes in living cells. I will discuss available technologies and the importance of the correct quantitative analyses of these processes. I will argue that there is a great deal of important data that we still can’t measure and that our understanding of dynamic cell systems remains very limited.
I will initially focus on the measurement of transcription dynamics. This part of the presentation will discuss our approach of using reporter gene imaging for the quantitative analysis of stochastic transcription pulses from single gene copies in individual cells. Initially, I will discuss some of the practical challenges of long term non-invasive cell imaging and I will briefly address the advantages and the disadvantages of the use of luminescence compared to fluorescence imaging. I will then discuss insights that have arisen from our work using combined fluorescence and luminescence imaging. I will describe how regular (oscillatory) pulses of transcription may arise from single gene copies due simply to the timing of transcription delays, [1].
I will next outline our current understanding of the NF-κB signalling system. I will discuss the possible implications of our discovery of NF-κB nuclear cytoplasmic oscillations, [2], and our observation that their frequency can control the pattern of downstream gene expression, [3]. I will also address cell-to-cell heterogeneity in the timing of NF-κB oscillations and its potential functional importance. I will discuss possible causes of heterogeneity following low dose stimulation, [4], and the role of negative feedback delays in the generation of cellular heterogeneity, [5]. I hope that this informal presentation can give rise to a discussion on the origin and function of oscillatory and pulsatile processes in cell biology.