Nestled deep in the nucleus of each of your cells is what seems like a magic trick: Six feet of DNA is packaged into a tiny space 50 times smaller than the width of a human hair. Like a long, thin string of genetic spaghetti, this DNA blueprint for your whole body is folded and compacted into structures called chromosomes in order to fit within this space.
Also packed into the nucleus are structures called nuclear bodies, which are proteins that act like cellular machinery. And as if DNA and nuclear bodies were not enough to fit into the volume of a cubic micrometer, strands of RNA (that will be translated to proteins) are also crammed in throughout the nucleus.
The three-dimensional, spatial organization of the nucleus is important; it varies between individual cells and can contribute to differences in cellular states, for example, the phenotype of a brain cell versus a muscle cell.
Now, Caltech researchers have developed a new technique to image the nucleus, including its DNA, RNA, and proteins. This new technology, dubbed seqFISH+, has enabled the team to make multiple new discoveries about how the organization of the nucleus influences cellular function.
A paper about the research, conducted in the laboratory of Long Cai, professor of biology and biological engineering, appears in the journal Nature on January 27, 2021. Cai is an affiliated faculty member with the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech.