Regulation of eukaryotic gene expression occurs at multiple levels, and can vary depending on the gene. For example, the subcellular expression of β-actin is controlled by the localisation of its mRNA to actin-rich peripheral regions of migrating cells. On page 1761, Yaron Shav-Tal and colleagues report a novel system for spatio-temporal quantification of β-actin expression. They create a human cell line expressing a transcriptionally inducible form of the chicken β-actin gene (ACTB) that enables visualisation of the gene, the transcribed mRNA and the translated protein in individual cells. They first show that the rtTA transcription factor binds to the ACTB promoter only transiently, for an average of 40 seconds. Four-dimensional imaging shows that, in this inducible system, the rate of transcription gradually increases to a maximum after ~1 hour, then gradually decreases. In agreement with previous findings, the authors also report that β-actin mRNA is elongated at a speed of 3.3 kb/minute and, once exported from the nucleus, moves through the cytoplasm by diffusion. Notably, β-actin mRNA that is stimulated to localise to the cell periphery derives from a pre-existing mRNA pool, rather than from newly transcribed mRNA produced following induction. So, the initial localization of β-actin mRNA to the cell periphery is not coupled to the initiation of β-actin transcription in the nucleus. This is the first study to follow the complete cellular pathway of a protein-coding mammalian mRNA in live cells.
Quantifying mRNA in space and time
Quantifying mRNA in space and time. J Cell Sci 15 May 2010; 123 (10): e1002. doi:
Download citation file:
Advertisement
Cited by
JCS Journal Meeting 2023: Imaging Cell Dynamics

Our 2023 Journal Meeting on ‘Imaging Cell Dynamics’ will be held from 14-17 May 2023 in Lisbon, Portugal. We have a limited number of spaces left so sign up now! Registration deadline: 31 March.
Call for papers: Cell and Tissue Polarity
-PolarityCFP.png?versionId=4491)
We are welcoming submissions for our next special issue, which will focus on ‘Cell and tissue polarity’ and will be guest edited by David Bryant. Submission deadline: 15 July.
Webinar: Increasing the visibility and impact of your research
-HUBSwebinar.jpg?versionId=4491)
Would you like to increase the visibility and impact of your research and raise your profile internationally? If so, register for the very practical webinar we are running in association with HUBS on 23 February 2023.
Cell scientist to watch: Gautam Dey

We interviewed Gautam Dey, who became a group leader at EMBL in Heidelberg, Germany, in 2021. His lab investigates the fundamental organisational principles and evolutionary dynamics of the nuclear compartment across eukaryotes.
Mechanisms of eukaryotic transcription termination at a glance

Check out our latest Cell Science at a Glance article and accompanying poster for an overview of the current understanding about the mechanisms of transcription termination by the three eukaryotic RNAPs.