Gene Shorts! E06

Three Blind Mice


One small step for science, one furry leap for mousekind. Scientists have found a way to reverse a common mutation that causes blindness in both people and mice using gene editing technology.

Co-Hosted by:

Phoebe Melvin, Producer at Genome BC


Dr. Kaylee Byers: Apparently. So where, hello? I am awaiting patiently here. Totally professional, and I know what I’m doing. It’s Dr. Byers, or you can call me Kaylee.

Phoebe Melvin: And I’m Producer Phoebe.

Dr. Kaylee Byers: Welcome to Gene Shorts. Right, I got it.

Read Transcript

Singer: (singing)

Dr. Kaylee Byers: Ugh, this song. This song. Why are we playing it?

Singer: (singing)

Dr. Kaylee Byers: As someone who has caught many rats in their life, this song is maybe not top of my list.

Phoebe Melvin: No? Oh, I’m surprised. I just thought we should listen to this to get us in the mood for today’s topic.

Dr. Kaylee Byers: Okay, well then no delay. Sally fourth.

Phoebe Melvin: All right. Kaylee, what if I told you that those poor three mice didn’t need to be blind after all?

Dr. Kaylee Byers: Well, I mean, I’d say fabulous for those mice. I truly would. I’d also say I’d be delighted to never listen to that song again. So, win-win.

Phoebe Melvin: Right. Well, great news for you then. Researchers in Wuhan, China have actually been able to reverse blindness in mice. And they’ve done this using CRISPR, which it’s sort of a type of gene editing. So they were able to use gene editing to bring back vision in mice with a condition called retinitis pigmentosa, which is a condition where a gene that encodes a critical enzyme called PDE6B is able to be corrected using a special type of CRISPR technique called PESPRY. There’s lots of acronyms in here, sorry.

Dr. Kaylee Byers: Love this, love this.

Phoebe Melvin: Let’s call it PESPRY.

Dr. Kaylee Byers: Why not?

Phoebe Melvin: And PESPRY is able to correct a variation in the gene that encodes the enzyme. And by correcting that genetic difference, they’re able to prevent the death of rods and cone photoreceptors in the eyes of these mice.

Dr. Kaylee Byers: Well, that sounds great. But to know why having these cells not die is a good thing, what do rods and cones do?

Phoebe Melvin: Yeah, great question. So rods and cones are types of cells that are in the back of the eyes of humans, and a lot of species actually. And the rod cells are responsible for vision in sort of low-light levels. And then the cones are active at higher-light levels, and they’re capable of color vision. And so together, they can help us see both in darker conditions, lighter conditions, and help us differentiate color.

Dr. Kaylee Byers: Okay. So in retinitis pigmentosa, we’ve got this mutation where these cells aren’t working, right? Is there anything else that retinitis pigmentosa does?

Phoebe Melvin: Yeah, so retinitis pigmentosa, get ready, another acronym shortened to RP is sort of a group of rare eye diseases that affect the retina. So that’s the back of the eye that we were just talking about, where the rods and cones are. And so RP makes the cells in the retina break down slowly over time, which can lead to loss of vision.

Dr. Kaylee Byers: So we’ve got these mice with retinitis pigmentosa. They say, we’re going to switch stuff up a bit, we’re going to do a little gene editing. I mean, how do they test that? How do they know it’s working in the mice?

Phoebe Melvin: Yeah. Well, you can’t really ask a mouse if their vision has changed.

Dr. Kaylee Byers: Don’t tell me what I can and cannot do. I’ll ask them if I please.

Phoebe Melvin: Sorry. You could try to ask a mouse.

Dr. Kaylee Byers: Thank you.

Phoebe Melvin: But what the people who conducted this study did, I mean it sounds a little bit cruel, but they put them into a maze.

Dr. Kaylee Byers: The little mice, they put them in a maze.

Phoebe Melvin: So our PESPRY mice, if you will, they put them into a sort of water maze. And the researchers observed how they would go navigating a maze that would require sight to get through. And as the researchers watched these PESPRY mice, they made it through with as much success as the mice who hadn’t been living with retinitis pigmentosa.

And then, just to double check that actually these results were real and that it was something that was truly happening with these mice, they tested to see if the mice reacted to visual stimuli. So, lights and things that they displayed to these mice. And they actually turned their furry little heads back and forth in response to these lights. So it was further proof that the PESPRY had prevented the death of the, or reversed rather, the death of the rods and cones in the back of their eyes.

Dr. Kaylee Byers: That’s very exciting for these little mice. But we are talking about mice here. I mean, how might this affect people?

Phoebe Melvin: It’s quite common, really. It affects the vision of one in 4, 000 people. So I think there’s about a hundred genes that can be affected and cause` this condition. So the researchers are hoping now that they’ve got proof that this PESPRY in these mice living with retinitis pigmentosa, that they’re able to reverse the condition. The next step would be to see if they can continue and replicate this study. And then maybe one day in the future it will lead to trials in humans, which could reverse retinitis pigmentosa in people living with that condition as well.

Dr. Kaylee Byers: Now, that’s very exciting. Thank you so much for coming in to share this. I mean, I love my stylish specs, but as someone who’s very nearsighted, I mean, I’m very excited about things that might mean that I don’t have to wear them quite so frequently all the time.

Phoebe Melvin: Yeah. Look, I don’t think it’s going to be happening overnight, but let’s keep our fingers and little mouse paws crossed.

Dr. Kaylee Byers: And thank you for listening to another episode of Gene Shorts. If you love these bite-sized episodes, but want to sink your teeth into a full course, go have a listen to some of our previous episodes. I’m sure there’s something there that will satisfy your listening tastes. Until then, catch you later.

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Host: Kaylee Byers
Creative Director: Jen Moss
Strategy: Roger Nairn
Producer: Sean Holden
Content Creator: Phoebe Melvin
Audio Engineer: Patrick Emile
Cover Art Designer: Amanda Di Genova

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