Avian Bioreactor Systems: A Review

et al. 2021

Poultry Science

Virus injection into EGK-X embryos is a well-defined approach in avian transgenesis. This system uses a chicken ovalbumin gene promoter to induce transgene expression in the chicken oviduct. Although a reconstructed chicken ovalbumin promoter that links an ovalbumin promoter and estrogen-responsive enhancer element ( ERE ) is useful, a large viral vector containing the ovalbumin promoter and a target gene restricts viral packaging capacity and produces low-titer virus particles. We newly developed recombinant chicken promoters by linking regulatory regions of ovalbumin and other oviduct-specific genes. Putative enhancer fragments of the genes, such as ovotransferrin ( TF ), ovomucin alpha subunit ( OVOA ) , and ovalbumin-related protein X ( OVALX ), were placed at the 5`-flanking region of the 2.8-kb ovalbumin promoter. Basal promoter fragments of the genes, namely, pTF, lysozyme (p LYZ ) , and ovomucoid (p OVM ), were placed at the 3`-flanking region of the 1.6-kb ovalbumin ERE. The recombinant promoters cloned into each reporter vector were evaluated using a dual luciferase assay in human and chicken somatic cells, and LMH/2A cells treated with 0-1,000 nM estrogen, and cultured primary chicken oviduct cells. The recombinant promoters with linking ovalbumin and TF, OVOA, pOVM, and pLYZ regulatory regions had 2.1- to 19.5-fold ( P < 0.05) higher luciferase activity than the reconstructed ovalbumin promoter in chicken oviduct cells. Therefore, recombinant promoters may be used to efficiently drive transgene expression in transgenic chickens.

Section: Discussionmentioning

confidence: 99%

Development and in vitro evaluation of recombinant chicken promoters to efficiently drive transgene expression in chicken oviduct cells

Yang

et al. 2021

Poultry Science

“…Chickens especially have several significant advantages as bioreactors, such as large production of eggs per hen, easy mating, short generation time of transgenic lines for scaling up the production, and low maintenance cost. So far, many transgenic chickens have been generated as avian bioreactors by inducing random integration of recombinant protein expression vector into their genomes [122]. However, expressions of recombinant protein in eggs by random integration of transgenes were varied among transgenic chickens [123][124][125].…”

Section: Pharmaceutical Purposementioning

confidence: 99%

Current Approaches and Applications in Avian Genome Editing

Kim

2020

IJMS

Self Cite

Advances in genome-editing technologies and sequencing of animal genomes enable researchers to generate genome-edited (GE) livestock as valuable animal models that benefit biological researches and biomedical and agricultural industries. As birds are an important species in biology and agriculture, their genome editing has gained significant interest and is mainly performed by using a primordial germ cell (PGC)-mediated method because pronuclear injection is not practical in the avian species. In this method, PGCs can be isolated, cultured, genetically edited in vitro, and injected into a recipient embryo to produce GE offspring. Recently, a couple of GE quail have been generated by using the newly developed adenovirus-mediated method. Without technically required in vitro procedures of the PGC-mediated method, direct injection of adenovirus into the avian blastoderm in the freshly laid eggs resulted in the production of germ-line chimera and GE offspring. As more approaches are available in avian genome editing, avian research in various fields will progress rapidly. In this review, we describe the development of avian genome editing and scientific and industrial applications of GE avian species.

“…Additionally, the relatively simple protein composition of egg white facilitates purification of the target protein. Since on these characteristics, the chicken egg has been recognized as an optimal bioreactor for production of therapeutic proteins [ 85 , 86 ]. Each egg white contains an average of 3.5 g of protein, of which ovalbumin constitutes half [ 85 , 87 ].…”

Section: Application Of Genome-edited Poultry In Industriesmentioning

confidence: 99%

Precise Genome Editing in Poultry and Its Application to Industries

Park

Han

2020

Genes

Poultry such as chickens are valuable model animals not only in the food industry, but also in developmental biology and biomedicine. Recently, precise genome-editing technologies mediated by the CRISPR/Cas9 system have developed rapidly, enabling the production of genome-edited poultry models with novel traits that are applicable to basic sciences, agriculture, and biomedical industry. In particular, these techniques have been combined with cultured primordial germ cells (PGCs) and viral vector systems to generate a valuable genome-edited avian model for a variety of purposes. Here, we summarize recent progress in CRISPR/Cas9-based genome-editing technology and its applications to avian species. In addition, we describe further applications of genome-edited poultry in various industries.