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CRISPR/CAS-mediated deletion of the upstream regulatory sequences enhances the estrogen-independent expression of chicken ovalbumin
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  • Sara Yousefi Taemeh,
  • Nima Dehdilani,
  • Lena Goshayeshi,
  • Jalil Merhzad,
  • Hesam Dehghani
Sara Yousefi Taemeh
Ferdowsi University of Mashhad Faculty of Veterinary Medicine
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Nima Dehdilani
Ferdowsi University of Mashhad Faculty of Veterinary Medicine
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Lena Goshayeshi
Ferdowsi University of Mashhad Faculty of Veterinary Medicine
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Jalil Merhzad
University of Tehran Faculty of Veterinary Medicine
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Hesam Dehghani
Ferdowsi University of Mashhad Faculty of Veterinary Medicine
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Abstract

Avian transgenesis has served as a suitable approach to generate bioreactors for the manufacturing of recombinant proteins. Production in chicken cells comes with significant advantages over other systems including providing the human-like glycosylation on target proteins. In this regard, the oviduct-specific ovalbumin promoter has been one of the ideal candidates to drive the expression of transgenes. Previous plasmid-based studies on the regulatory sequences of ovalbumin promoter have led researchers to exploit ovalbumin regulatory elements out of their native genomic context (ex situ) to direct transgene expression in the transgenic chicken bioreactors. Although the inherent limitations on the ex situ use of ovalbumin promoter have promoted the use of native ovalbumin promoter for the expression of a transgene, generation of transgenic chicken is relatively difficult, inefficient, and time-consuming. To overcome these obstacles, in this study we show that CRISPR-mediated deletion of some distal ovalbumin promoter sequences in a non-oviduct cell can lead to the significant expression of the ovalbumin gene, and also a knocked-in reporter, in an estrogen-independent manner. These findings overcome the limitation of cloned promoters, where the promoter regulatory sequences have to be taken out of their cis context and also their native spatial nuclear organization into a plasmid.

Peer review status:POSTED

09 May 2020Submitted to Biotechnology and Bioengineering
11 May 2020Assigned to Editor
11 May 2020Submission Checks Completed