Commentary: Genetic modification through oligonucleotide-mediated mutagenesis. A GMO regulatory challenge?

Abstract

In the European Union, the definition of a GMO is technology-based. This means that a novel organism will be regulated under the GMO regulatory framework only if it has been developed with the use of defined techniques. This approach is now challenged with the emergence of new techniques. In this paper, we describe regulatory and safety issues associated with the use of oligonucleotide-mediated mutagenesis to develop novel organisms. We present scientific arguments for not having organisms developed through this technique fall within the scope of the EU regulation on GMOs. We conclude that any political decision on this issue should be taken on the basis of a broad reflection at EU level, while avoiding discrepancies at international level.

Biotech Approaches to Overcome the Limitations of Using Transgenic Plants in Organic Farming

“…used to correct or to introduce site-specific mutation into genes. Mutagenesis is induced through the introduction of a chemically synthesized complementary chimeric DNA/RNA or DNA/DNA oligonucleotide (20-100 nucleotides in size) as well as single-stranded DNA, RNA, or triple-helix-forming oligonucleotides, designed to have one or more bases that do not pair with the endogenous gene sequence (Breyer et al 2009 and bibliography therein [20]). The helical distortion induced by the mismatch in the homology-directed pairing between the oligonucleotide and the DNA of the target region is subsequently recognized by the cell's DNA repair machinery and corrected (base substitution, addition, or deletion) using the DNA sequence of the chimera as a template; eventually, the oligonucleotide is naturally degraded (Sauer et al, 2016 [21]).…”

Relaxed chromatin induced by histone deacetylase inhibitors improves the oligonucleotide-directed gene editing in plant cells

“…By offering alternatives to traditional transgenesis, the progress in the improvement of these genomeediting technologies is of central significance as novel breeding techniques (Breyer et al 2009). Crops produced by these methodologies might have a greater acceptance by the GMO-conscious public, organizations and governments (Voytas and Gao 2014).…”

“…As an additional option, synthetic chimeric RNA/DNA molecules or single-stranded DNA oligonucleotides (SDOs) can be employed as vectors to produce oligonucleotide-targeted nucleotide exchange (OTNE) at a specific site of plant genomic DNA (Breyer et al 2009;Sauer et al 2016a;Sauer et al 2016b). The pioneering studies preferentially used chimeric RNA/DNA oligonucleotides for the induction of gene-specific mutations (Beetham et al 1999;Kochevenko and Willmitzer 2003;Okuzaki and Toriyama 2004;Ruiter et al 2003;Zhu et al 2000;Zhu et al 1999).…”

Transgenic, cisgenic and novel plant products

“…Techniques that introduce recombinant DNA molecules transiently to plants are ZFNs introduced into the cell with or without a repair template (ZFN1 and ZFN2), oligonucleotide-directed mutagenesis (ODM) (Breyer et al, 2007) and agroinfiltration that makes use of Agrobacterium to inject several foreign DNA molecules into the plant cells. These processes resemble transgenesis À in vitro synthesized nucleic acids and DNA delivery methods À but the end products are similar to, and indistinguishable from, plants obtained through conventional plant breeding.…”

“…Therefore, NPPs are in most cases undetectable (Lusser et al, 2011). Definitions according to the EU working group on new techniques are as follows: ODM uses oligonucleotides for targeted (site-specific) induction of point mutations (Breyer et al, 2007); ZFN1 generates site-specific random mutations by NHEJ; ZFN2 generates site-specific desired point mutations by DNA repair processes through HR.…”