Sister stem cell clues

Kat - One of the other stories I noticed this month is from the Institute of Cancer Research, but it's not actually a cancer story. It's a really nice piece of work, looking at stem cells. What the researchers have done is incredibly fiddly - I can just imagine some poor PhD student or post doc's life being ruined by this! - but they've taken stem cells growing in the lab in a dish - embryonic stem cells - and they've watched as they divide. They've picked out the two new sister or daughter cells that have been created from one cell dividing, sucked each of them up separately, and analysed all the genes that are switched on in those cells. It's an incredible technical feat. What they found was really fascinating because you'd expect two daughter cells that have just come from one cell to be the same. Actually, they had wildly different patterns of gene activity and this is kind of weird, I think.

Nell - Yeah. It's certainly not what you'd expect especially when you're kind of picturing these two little cells, surely they're exactly the same, but it turns out that they're not and it's kind of almost the next level from the story we were just talking about. So, you're not looking at the mutations, you're looking at more subtle changes to how the DNA is expressed, how it's switched on. It's really interesting to see that there's actually quite a lot of difference between two cells like that.

Kat - And they're starting to get a handle on what's causing this difference because they treated the stem cells with a cocktail of chemicals which is called 2i. Apparently, this reverts the cells back to a more stem cell-like state. It does this by interfering with the process called DNA methylation. This is basically like putting kind of Post-It notes on the DNA saying, "Don't use these genes. Use these genes." When you mess up that, they actually found that the stem cells were a lot more similar and this is delving into the territory of epigenetics and showing that that's probably responsible for some of these differences.

Nell - Yeah. I mean, I think this is really interesting because when you sort of start to get into learning about DNA and you get all these stuff about you know, all our cells in the body have the same genetic code. You start to think, "Well, how come some of them do one thing and some of them do another thing?" And this is really getting to the heart of that and helping us to understand how one stem cell can give rise to all these different types of cell that go on to do amazingly specialised things. So, it has got some implications probably for some types of diseases, but really, this is just kind of understanding the whole process at the fundamental level.

Kat - I think it's absolutely fascinating and a real technical tour de force.