![]() This is a more informative application of what’s going on by a factor of 10.” You can subset that into five to 10 subpopulations, each of which has the potential to either expand or go away. “We found that we can take a purified population of B cells, as pure as we can make it, and nevertheless every cell is different from every other cell. We think that in five years you will not be able to produce a first-rate paper or get a top grant without this technology.”įive years ago, Mountz’s lab dove into single-cell work, “bootstrapping with our own money and equipment that we had to write a grant to obtain,” he said. “Just during my career, I’ve seen this go from northern blot to real-time PCR looking at smaller amounts of RNA, to flow cytometry looking at 50 markers per cell, to single-cell, where we can have a complete characterization of an individual cell. “Every decade or so there’s another revolution in immunology,” he said. In some ways, that’s just more of the same for Mountz. Immunology is not being done the way it was 10, five, even three years ago.” (For the most part, the single-cell sequencing we’re talking about here is RNA-sequencing, or single-cell RNAseq, but there are other varieties, including V(D)J sequencing to profile the adaptive immune repertoire and ATAC-seq - Assay for Transposase-Accessible Chromatin using sequencing - to understand chromatin accessibility.) You can really tell what genes are being expressed - not what the potential functional elements are at the DNA level, but what is actually steering the cell. “Single-cell sequencing is revolutionizing immunology,” said John Mountz, M.D., Ph.D., Goodwin-Blackburn Chair and Professor in the Department of Medicine Division of Clinical Immunology and Rheumatology. In five years you’ll be repeating what other people have done, but right now we’re at a moment that is wide open.” Today, practically anything you do will be a discovery - it hasn’t been done before at this level. ‘Amazing’ science “There’s a whole bunch of low-hanging fruit in every area of science. “And it is revealing new types of cells - cells that nobody had any idea existed that actually play key roles. “Single-cell sequencing gives us a much better window to understand how cells function in their microenvironment,” said Kent Keyser, Ph.D., assistant vice president for research at UAB. And when you do it this way, surprising things happen. Each individual cell in a sample can be handled separately. Single-cell sequencing, on the other hand, is like a fruit salad. (RNA, you’ll recall, transcribes the DNA code and shuttles it out of the nucleus where the code is used to manufacture the proteins that actually do the work of the cell.) Researchers compare it to a smoothie, with RNA transcripts from a host of individual cells all blended together in a mush. But if you’re curious about which genes are actually switched on in those cells, you will want to sequence the RNA transcripts that are present. This works out fine if you are interested in the genome itself. In order to get at their DNA, labs induce all of those cells to burst open, then they sequence all the genetic code that spills out. A saliva sample or cheek swab may contain millions of cells. It’s the way the body can make everything from a neuron to an egg cell using the same genome.īut traditional gene-sequencing obliterates much of this variety. And even within the same cell type, lots of different things are going on - that is, the 20,000 genes in your genome are turned on and off in different combinations. ![]() For starters, there are roughly 200 different types of cells - blood cells, nerve cells, muscle cells, skin cells, stem cells, fat cells and so on. Every one of your cells, in its nucleus, has a copy of your entire genome, all 3 billion or so A-C-T-G base pairs. Much like processed meats, gene-sequencing can be a questionable mixture. ![]() If each cell was a slice of thick-cut bologna, the pile would stretch more than halfway to the sun. "You can really tell what genes are being expressed - not what the potential functional elements are at the DNA level, but what is actually steering the cell.” There are 37.2 trillion cells in the human body, according to a 2013 study from Italy’s University of Bologna. The science made possible by sequencing individual cells "is just amazing," Mountz said. ![]() Shanrun Liu, John Mountz and Hui-Chen Hsu in the UAB Comprehensive Flow Cytometry Core, which houses a core facility for single-cell sequencing.
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