High-level expressing YAC vector for transgenic animal bioreactors

Area of Science:

• Biotechnology
• Genetics
• Animal Science

Background:

• Position effect is a significant challenge in creating transgenic animals for bioreactor applications.
• Efficient gene expression in mammary glands is crucial for producing therapeutic proteins.

Purpose of the Study:

• To assess the utility of a 210-kb human alpha-lactalbumin YAC vector for producing transgenic rats.
• To evaluate the efficiency and expression levels of human growth hormone (hGH) in the milk of these transgenic rats.

Main Methods:

• Homologous recombination was used to insert the hGH gene into YAC vectors.
• YAC DNA was microinjected into rat embryos to generate transgenic rats.
• hGH expression and tissue specificity were analyzed in the milk and mRNA of transgenic rats.

Main Results:

• Transgenic rats were successfully produced with YAC vector DNA, showing similar efficiency to plasmid constructs.
• All analyzed transgenic rats carried one copy of the transgene and secreted high levels of hGH (0.25-8.9 mg/ml) in their milk.
• hGH mRNA exhibited tissue specificity mirroring the endogenous rat alpha-lactalbumin gene.

Conclusions:

• The 210-kb human alpha-lactalbumin YAC vector is effective for high-level, tissue-specific expression of foreign genes in transgenic animal milk.
• This YAC vector system offers a promising solution for overcoming position effects in mammary gland bioreactor production.
• The findings support the use of YAC vectors for efficient production of therapeutic proteins in transgenic animals.