Visualizing the movements of genes in vivo
The Green fluorescent protein (GFP) is bound to a TALE protein, itself fixed on a DNA sequence. ©Yusuke Miyanari
Nat Struct Mol Biol Nov 2013
Oct. 6, 2013
Some regions of our DNA within the nucleus are highly mobile. Their dynamic changes within the nucleus can make genes accessible and this is therefore one of the mechanisms controlling their expression. Being able to observe the organization and movements of genes in time and space would therefore be a breakthrough to understand the resulting processes for the gene regulation. Maria-Elena Torres-Padilla’s team has just developed a promising method to visualize the mobility of genome in living organisms. These results are published on 4th October in Nature Structural & Molecular Biology.
About gene mobility
In the cell, DNA is actually highly dynamic within the nucleus. It is known that the physical position of genes changes according to whether they are 'active' or 'inactive'. The way the DNA is physically organized is a decisive element for gene expression, determining if genes are active or not. Better understanding genome dynamics within the nucleus is a crucial step to decipher the entire regulation of our genome and how genes are expressed or repressed.
Visualize gene movements through TGV
Discovered in bacteria, TALE proteins have emerged as “artificial” DNA binding proteins which recognize a specific target DNA sequence within a cell. Developed since 2009, this technology has been used so far to cleave targeted DNA sequences using TALE fused with a nuclease. Maria‐Elena’s team integrated the TALE technology to label target genomic sequences and visualize their movements in vivo. They fused a green fluorescent protein (GFP) to TALE, allowing visualization of subnuclear localization of satellite sequences in living cells. This method, called TGV (TALE‐mediated Genome Vizualisation), showed expected results and permitted to track labeled target DNA in real time.
Tracking male and female genes after fertilization?
All our cells contain a full set of chromosomes from our mother and a full set from our father. The TGV technology was also used by the team to label specifically chromosomes derived from the father or the mother, and to follow their localization over several cell divisions. The resulting videos speak for themselves and offer tremendous research perspectives to study the expression of parental alleles, and notably whether they behave and are expressed in the same way or not.