ATAC DO: The next generation of a technique called ATAC-seq, which captures and sequences active regions of DNA (1), allows for the visualization of these regions as well. In ATAC-see, a so-called transposome (2) uses a transposase enzyme (yellow) to insert a pair of fluorescent DNA tags into open regions of chromatin (3). Upon insertion, the DNA is cleaved (4) and the tags are visible under a microscope (5) human cells’ open chromatin labeled red). These tagged sections of DNA are then sequenced.© GEORGE RETSECK; XINGQI CHEN, STANFORD UNIVERSITY
In the limited space of the nucleus, most of the genome is tightly folded, leaving accessible only the parts that need to be transcribed. There is “huge interest” in determining which elements of the genome are active in a given cell type, says Howard Chang of Stanford University. This was Chang’s motivation for developing a technique called ATAC-seq (assay for transposase-accessible chromatin)—in which DNA tags (acting as transposons) are enzymatically integrated into open regions of the genome and then used to identify those regions through sequencing.
Chang described ATAC-seq in 2013, but says, “we were breaking the cell open to get this information, so we didn’t have any sense of the 3-D organization of the [accessible] elements.”
Fast-forward three years, and Chang has now developed ...
