| Popis: |
The ability to generate DNA double-strand breaks (DSBs) at specified locations in a plant’s genome, thereby stimulating the cell’s DNA repair processes, represents a promising means of facilitating genetic modification for both basic studies of gene function as well as applied crop improvement. Zinc finger nucleases (ZFNs) are engineered restriction enzymes consisting of a nonspecific cleavage domain and sequence-specific DNA-binding domains designed to create site-specific DSBs. Since DSB repair in plants appears to occur primarily via error-prone nonhomologous end joining (NHEJ) processes, ZFNs designed to cleave endogenous genes is a path toward targeted mutagenesis. Similarly, ZFN-mediated induction of concurrent DSBs can give rise to targeted deletions of genomic segments between cleavage sites. In addition, homology-directed repair of targeted DSBs allows for site-specific transgene integration into transgenic and endogenous gene loci as well as the creation of specific sequence modifications. The combination of sequence-specific DNA cleavage by designed ZFNs and homology-directed DSB repair at investigator-specified break sites makes precision genome modification a reality. This capability, in combination with rapid advances in genome sequencing and bioinformatics, bodes well for the future of plant functional genomics and crop improvement. |
