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YouDrink t1_iy0t0ll wrote

Reply to comment by Seicair in How exactly does CRISPR-CAS9 insert new genes? by AutomaticAd1918

Very common for 20-60 nucleotides, but can be done for 3000 nucleotides.

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CompMolNeuro t1_iy14ulx wrote

Just extra fun information. There are other gene transmission methods that can carry up 30 or 40 thousand nucleotides, like repacking a retrovirus, though it's not organism wide and the research has probably been set aside since I last saw the inside of a lab.

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MarsLumograph t1_iy1jbkt wrote

But they are not talking about gene transmission? They are talking about DNA synthesis. How many nucleotides can you add with that method.

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Iniquitous33 t1_iy1yhto wrote

That method generally stops being efficient as you get to the higher double digits, but you can stitch those double digit length pieces together after they've been synthesized using a different chemical process. That makes the manufacture of these 40Kmers or really any conceivable length possible - though certainly not practical or economical.

Manufactured oligonucleotide material is very expensive relative to small molecule or even antibody medicines. The industry is working to solve that, as it's a relatively newer type of medicine, but whoever can figure that out will dramatically open up treatments for rare disease and personalized medicine, as well as bringing the cost down for tons of quality of life treatments that exist and are great, but are cost prohibitive vs standard treatments that work but only ok, or have side effects that suck but aren't bad enough to justify a treatment that's 50x more expensive.

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MarsLumograph t1_iy2ktcy wrote

I don't think DNA synthesis is the main limiting factor for gene therapy, but delivery and safety.

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Iniquitous33 t1_iy38r0x wrote

I was actually referring to ASO, siRNA, and other direct oligonucleotide therapeutics. These are viable right now, safe and effective. Gene therapy is kind of "next in line" as it were, but as you implied still has some major kinks to be worked out. Though I believe it will be relatively figured out given time. I'm pretty excited to see what the next decade holds for the field at large.

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Outrageous_Cry_5945 t1_iy2akdm wrote

Also AAV, adeno-associated viruses . . . (but not preferable in a clinical setting/application usually, since they apparently can sometimes elicit immune responses and may contribute to the deaths of some patients historically in gene therapy trials https://www.nature.com/articles/s41587-020-0642-9 High-dose AAV gene therapy deaths, liver dysfunction, sepsis . . . )

Edit: I suspect that if we can use nanolipid particles as vectors, that may be more safe instead of AAV vectors.

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