Virus-like particles carry gene editors into pig and chicken models
Researchers used virus-like particles to deliver gene-editing proteins into pig and chicken experimental models. The peer-reviewed work covered cultured cells, small laboratory-grown tissues, oocytes and chicken embryos. Temporary protein delivery enabled several types of genetic changes, while applications in adult animals and the method’s long-term safety still require investigation.
Science··Morning
Proteins arrive without a lasting editor vector
Virus-like particles delivered gene-editing proteins to experimental pig and chicken models in a peer-reviewed study published on 11 November. The work covered cells, small laboratory-grown tissues, oocytes and chicken embryos. Researchers used particles that imitate the ability of viruses to enter cells and carry molecular cargo. Fluorescent proteins helped them check whether the carrier reached the cells before they assessed the genetic changes.[1], [2]
The cargo included Cre recombinase, an enzyme used to rearrange DNA, and Cas9, the DNA-cutting component of the CRISPR gene-editing system. A further version, dCas9, had its cutting function disabled. The particles supplied these tools as temporary protein cargo, in place of a DNA vector continuously encoding the editor. Pig connective-tissue cells were among the cell types used in the experiments.[1]
Pig cultures and oocytes undergo targeted changes
In pig colon organoids, the small cultured tissues used to model organs, Cre activated genetic variants previously installed in KRAS and TP53. Researchers subsequently followed changes in the cultures’ shape. Fluorescence marked protein entry, while DNA sequencing established changes at the targeted sites. For Cas9, the way guides were packaged affected editing: mixing two particle batches manufactured separately, each carrying a different guide RNA, worked better than manufacturing one batch containing both guides.[1]
After microinjection into pig oocytes, targeted edits were found in some of the developing blastocysts. In a separate use of the platform, dCas9 changed methylation at a regulatory region of TP53 in pig cells.[1]
Chicken embryos show editing in sampled immune tissue
Particles were administered to chicken embryos on developmental day 12. Seven days later, editing was detected in all nine sampled bursae, an immune tissue. The wider avian experiments also included cell cultures and cultured tracheal tissue. The authors propose eventual uses in gene research and disease models, including the possibility of reducing breeding for certain genetic animal lines. They did not measure a reduction in animal use. Distribution to adult tissues, unwanted edits, immune responses and long-term safety remain subjects for further investigation.[1]
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