Study of the regulatory elements of the Ovalbumin gene promoter using CRISPR technology in chicken cells

BackgroundHormone-dependent promoters are very efficient in transgene expression. Plasmid-based reporter assays have identified regulatory sequences of the Ovalbumin promoter that are involved in response to estrogen and have shown that the deletion of the steroid-dependent regulatory element (SDRE) and negative regulatory element (NRE) leads to a steroid-independent expression of a reporter. However, the functional roles of these regulatory elements within the native genomic context of the Ovalbumin promoter have not been evaluated.ResultsIn this study, we show that the negative effects of the NRE element on the Ovalbumin gene can be counteracted by CRISPR interference. We also show that the CRISPR-mediated deletion of SDRE and NRE promoter elements in a non-oviduct cell can lead to the significant expression of the Ovalbumin gene. In addition, the targeted knock-in of a transgene reporter in the Ovalbumin coding region and its expression confirms that the truncated promoter of the Ovalbumin gene can be efficiently used for an estrogen-independent expression of a foreign gene.ConclusionsThe methodology applied in this paper allowed the study of promoter regulatory sequences in their native nuclear organization.

Automated summary

This study demonstrates the counteraction of negative regulatory elements in the Ovalbumin gene by CRISPR interference, and reveals the possibility of achieving estrogen-independent expression of the Ovalbumin gene through the deletion of steroid-dependent regulatory elements and negative regulatory elements.