Genome
engineering, in the colloquial speech often denoted as “gene manipulation” is a
politically, socially and economically lively debated topic with proponents and
opponents coming from different lobbies. It is undisputed that Technologies
for making and manipulating DNA have enabled advances of great importance. One
of these technologies, the CRISPR/Cas9 is highly topical as it has been
declared by the Science-magazine as
the „Breakthrough oft the Year 2015“.
In the mid 2000s, scientists discovered so called CRISPRs (clustered
regularly interspaced short palindromic repeats) in the genome of Escherichia coli. Later on, CRISPRs have
been detected in various species of bacteria and archae (Doudna &
Charpentier, 2012). These sequences are part of the CRISPR/Cas system which acts
as a protection mechanism against viral invasion. CRISPR-associated proteins
(Cas) are able to bind and specific RNA sequences , the so called crRNA-repeat
sequence. This sequence is followed by a crRNA-spacer sequence which is
determining for its binding on the tareted DNA sequence. In turn, the enzyme
endonuclease Cas9 cuts this DNA in its close environment. With this ability,
the CRISPR/Cas system is able to find, cut and destroy viral DNA.
Due to the the ability of this system to edit specific sequences of the DNA
with a high precision it can be used as a mechanism to edit eukaryotic DNA as well,
as J. Doudna and E. Charpentier discovered in 2012. The simplicity of this
system makes it highly interesting as it only requires three components (crRNA,
trRNA and tha Cas9 enzyme).
Meanwhile, the CRISPR/Cas9 system has been successfully used to target important
genes in a broad variety of species including plants and humans (Reis, 2014). Presumably
the targeting and editing of genes in plants of agronomic interests is going to
be the most important application area. For example
the team around Dr. Cristobal Uauy tried to target a gene coding for a
plasma membrane protein which is thought to be involved in grain dormancy.
Despite of all the advantages this type of technology definitely has, its
usage is to handle with care. Concerning the near future of this technology,
the focus should lay on a suggestive regulation on the application of such a biochemical
“superweapon”.
References:
Doudna, J.A. & Charpentier, E. (2014). The new frontier of genome engineering with CRISPR-Cas9.
http://blogs.biomedcentral.com/on-biology/2015/11/30/using-crisprcas9-genetically-modify-crops/
https://www.neb.com/tools-and-resources/feature-articles/crispr-cas9-and-targeted-genome-editing-a-new-era-in-molecular-biology
