Video: Transcription, live

For the first time, scientists have devised a way to watch and analyze, in real time, the transcription of a single gene in a living human cell. Published online today (July 18) in Nature Methods, researchers at Bar-Ilan University in Israel describe their system to visualize and track the kinetics of transcription, including the speed and fluctuations of transcription of a single gene. Yaron Shav-Tal and colleagues at Bar-Ilan used their technique, which involves tagging the mRNA product from

For the first time, scientists have devised a way to watch and analyze, in real time, the transcription of a single gene in a living human cell. Published online today (July 18) in Nature Methods, researchers at Bar-Ilan University in Israel describe their system to visualize and track the kinetics of transcription, including the speed and fluctuations of transcription of a single gene. Yaron Shav-Tal and colleagues at Bar-Ilan used their technique, which involves tagging the mRNA product from a single gene copy with green fluorescent protein, to track the speed and duration of the transcription of a single cyclin D1 allele, a well-characterized gene that produces a protein important to the cell cycle. By tracking the gene multiple times, the team was able to detect how many mRNA transcripts were produced, how quickly they were produced, and how different types of promoters affect the rate of transcription. Here, we share four videos the researchers made of the process:

Movie 1: A single cyclin D1 gene in a human cell is continuously transcribing. This version of the gene is driven by a cytomegalovirus promoter and produces mRNAs without a stop. The nascent transcripts are detected as they emerge from the gene by the binding of a green fluorescent protein. (Actual movie is 1 hour long.)

Movie 2: A single cyclin D1 gene in a human cell begins to transcribe. In this case, an endogenous promoter regulates the gene, resulting in transcription that is not constant but occurs in bursts, like this one. (Actual movie is 2 hours long.)

Movie 3: Again controlled by an endogenous promoter, a single cyclin D1 gene cycles between "on" and "off" states (bottom cell). (Complete movie is 6+ hours long.)

Movie 4: After replication of the genome (S phase), the cell contains double the amount of DNA, including 2 copies of the tagged cyclin D1 gene. We can detect the transcribing "mother" transcription site and the emergence of the "daughter" transcribing allele situated right beside it (active transcription sites are enlarged and pseudo-colored on the right). (Complete movie is 44 minutes long.) Videos courtesy of Yaron Shav-Tal, Bar-Ilan University. S. Yunger et al. "Single-allele analysis of transcription kinetics in living mammalian cells," Nature Methods, published online July 18, 2010, doi:10.1038/nmeth.1482
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