
Alternative CRISPR system could improve genome editing - etiam
http://www.nature.com/news/alternative-crispr-system-could-improve-genome-editing-1.18432
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tomkinstinch
From the Broad's press release, on how the new system is different[1]:

"The newly described Cpf1 system differs in several important ways from the
previously described Cas9, with significant implications for research and
therapeutics, as well as for business and intellectual property:

First: In its natural form, the DNA-cutting enzyme Cas9 forms a complex with
two small RNAs, both of which are required for the cutting activity. The Cpf1
system is simpler in that it requires only a single RNA. The Cpf1 enzyme is
also smaller than the standard SpCas9, making it easier to deliver into cells
and tissues.

Second, and perhaps most significantly: Cpf1 cuts DNA in a different manner
than Cas9. When the Cas9 complex cuts DNA, it cuts both strands at the same
place, leaving ‘blunt ends’ that often undergo mutations as they are rejoined.
With the Cpf1 complex the cuts in the two strands are offset, leaving short
overhangs on the exposed ends. This is expected to help with precise
insertion, allowing researchers to integrate a piece of DNA more efficiently
and accurately.

Third: Cpf1 cuts far away from the recognition site, meaning that even if the
targeted gene becomes mutated at the cut site, it can likely still be re-cut,
allowing multiple opportunities for correct editing to occur.

Fourth: the Cpf1 system provides new flexibility in choosing target sites.
Like Cas9, the Cpf1 complex must first attach to a short sequence known as a
PAM, and targets must be chosen that are adjacent to naturally occurring PAM
sequences. The Cpf1 complex recognizes very different PAM sequences from those
of Cas9. This could be an advantage in targeting some genomes, such as in the
malaria parasite as well as in humans."

1\.
[https://www.broadinstitute.org/news/7272](https://www.broadinstitute.org/news/7272)

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benchtobedside
Can anyone comment on how this may impact the IP landscape for CRISPR? [0]

[0] [http://www.the-
scientist.com/?articles.view/articleNo/42595/...](http://www.the-
scientist.com/?articles.view/articleNo/42595/title/Who-Owns-CRISPR-/)

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josaka
Zhang's patent US 8,697,359 is limited to techniques in which "the Cas9
protein cleaves the DNA molecule." If this new technique does not use the Cas9
protein in this fashion, it would potentially provide a design-around, meaning
that the benefit of the patented idea can be obtained without infringing the
patent.

New patents may have issued that are not so limited.

~~~
benchtobedside
Thanks for clarifying.

Further to this comment from [0]: "But with Cfp1, the stakes of that specific
patent dispute go down. A lab or company could use Cfp1 without infringing on
the CRISPR/Cas9 patent. "

[0] [http://www.wired.com/2015/09/war-genome-editing-just-got-
lot...](http://www.wired.com/2015/09/war-genome-editing-just-got-lot-
interesting/?mbid=social_twitter)

