Light-Synchronized Transcription Dynamics Indicates cis-Regulation of Transcription at Refractory Promoters
Event details
| Date | 15.07.2014 |
| Hour | 11:15 |
| Speaker | Prof. Michael Brunner, Biochemistry Center, Heidelberg University (D) |
| Location | |
| Category | Conferences - Seminars |
BIOENGINEERING SEMINAR
Abstract:
Transcription of genes appears to be a smooth process when analyzed in an ensemble of cells. However, on the level of a cell many genes appear to be transcribed in random bursts followed by periods during which promoters are refractory towards re-stimulation. We used the light-dependent transcription factor White Collar Complex of Neurospora crassa as an optogenetic tool to study transcriptional bursting in a population approach. Activation of the WCC by a light pulse triggers a synchronized wave of transcription from the frequency promoter followed by an extended refractory period of more than 1 h. When challenged by a second light pulse, stable binding of Pol II and phosphorylation of its C-terminal domain repeats at serine 5 is impaired. We present evidence that refractory promoters carry a physical memory of their previous history.
Bio:
Michael Brunner is the director of the Heidelberg University Biochemistry Center and full professor since 2000 leading the "Circadian Rhythms and Molecular Clocks" group. Their aim is to understand how the circadian clock works as a program that coordinates complex expression profiles in a temporal fashion, using the filamentous fungus Neurospora crassa as a model organism. The mechanisms underlying the positive and negative feedback loops of the molecular clock and the temporal and spatial coordination of the various clock protein interactions are in the main focus of the research. The FRQ/WCC oscillator modulates rhythmic expression of about 1000 Neurospora genes. Only a fraction of these genes are directly controlled by WCC. The organization and regulation of the network of clock-controlled genes is a further focus of the lab.
Abstract:
Transcription of genes appears to be a smooth process when analyzed in an ensemble of cells. However, on the level of a cell many genes appear to be transcribed in random bursts followed by periods during which promoters are refractory towards re-stimulation. We used the light-dependent transcription factor White Collar Complex of Neurospora crassa as an optogenetic tool to study transcriptional bursting in a population approach. Activation of the WCC by a light pulse triggers a synchronized wave of transcription from the frequency promoter followed by an extended refractory period of more than 1 h. When challenged by a second light pulse, stable binding of Pol II and phosphorylation of its C-terminal domain repeats at serine 5 is impaired. We present evidence that refractory promoters carry a physical memory of their previous history.
Bio:
Michael Brunner is the director of the Heidelberg University Biochemistry Center and full professor since 2000 leading the "Circadian Rhythms and Molecular Clocks" group. Their aim is to understand how the circadian clock works as a program that coordinates complex expression profiles in a temporal fashion, using the filamentous fungus Neurospora crassa as a model organism. The mechanisms underlying the positive and negative feedback loops of the molecular clock and the temporal and spatial coordination of the various clock protein interactions are in the main focus of the research. The FRQ/WCC oscillator modulates rhythmic expression of about 1000 Neurospora genes. Only a fraction of these genes are directly controlled by WCC. The organization and regulation of the network of clock-controlled genes is a further focus of the lab.
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