פרופ' ירון שב-טל

Our research focuses on the gene expression pathway, and specifically on mRNA dynamics in living cell systems. We study dynamic cell processes on the single-molecule, single-gene and single-cell level using time-lapse fluorescent microscopy and subsequent kinetic analysis.

The primary goals of our research are to understand how genes switch "on" and "off" in normal cells and in cancer cells, how quickly are mRNAs transcribed, the kinetics of the transcription process in vivo, and their travels and destinations as they translocate within the cell. The major topics of interest in our group:

Cancer and Gene Expression

We follow gene expression in real-time by applying a variety of fluorescent tags to genes, mRNAs and proteins, and have developed a number of cell systems in which gene expression, or mRNA transcription, can be examined and quantified.

We are able to observe single genes in living cells and to quantify the action of a gene as it unfolds before our eyes. Using this approach, we can monitor the influence of promoter regions and transcription factors, on the activity of an oncogene in living cells, thereby elucidating the over-expression pathway in cancerous cells.

As the process of transcription transpires, the pre-mRNA undergoes a number of processing events such as capping, splicing and polyadenylation. Since these processes occur co-transcriptionally, it is important to determine whether they affect transcription kinetics. We are examining the real-time kinetics of the co-transcriptional process of pre-mRNA splicing using live cell imaging techniques (FRAP, photoactivation and FCS) followed by kinetic modeling for analysis of the kinetic data.

RNA Export

In order to understand how genetic information disseminates from the cell nucleus into the cytoplasm it is essential to determine the mechanisms of mRNA mobility in cells. We have been following the dynamics of mRNA nucleoplasmic translocation, as well as mRNA export in vivo. We are interested in analyzing different elements that control the export pathway, using inhibitors and knock down of specific elements considered necessary for these processes. Our analysis performed by applying single molecule approaches that allow us to quantify the interactions of molecules passing through the nuclear pore complex. We also perform screening of small molecule libraries using high-content microscopy in search of new inhibitors of the gene expression pathway.

Cytoplasmic mRNA

Cytoplasmic mRNAs can be translated by ribosomes, stored in granules, or degraded by a variety of surveillance mechanisms. A group of structures involved in mRNA storage and decay are cytoplasmic P-bodies. We are interested in understanding the dynamics of cytoplasmic P-bodies in living cells in relation to mRNA kinetics. Imaging the "mRNA localization" process in real-time will assist in revealing the fate of mRNAs in cells.

For more details see our lab website: lifefaculty.biu.ac.il/shav-tal/