For more than 20 years, plant biologists have tried to achieve complete control of transgene expression. However, until the techniques to target transgenes to safe harbor sites in the genome become routine, we need to find methods to avoid avoid positional effects.
Due to the random nature of transgene insertion in the majority of higher eukaryotes, transgenic DNA may integrate into regions of the genome that are transcriptionally repressed, which can result in many cases in transgene silencing. Additionally, transgenes may be incorporated near endogenous regulatory elements, such as transcriptional enhancers or repressors, which can cause their miss-expression
Flanking transgenes with "genetic insulators", DNA sequences that create independent domains of gene expression, can help stabilize them.
We have studied the effect of four different "insulator" sequences over transgene expression levels and variability, and over transgene integration, using NGS. Our results compare the benefits obtained and suggest that different sequences should be used depending on the specific needs of each biotechnology project.
Pérez-González, A., Caro, E. 2019. Benefits of using genomic insulators flanking transgenes to increase expression and avoid positional effects. Scientific Reports 9, 8474. DOI: 10.1038/s41598-019-44836-6