Identification of CHO endogenous gene regulatory elements.

Area of Science:

• Biotechnology and Genetic Engineering
• Cellular and Molecular Biology
• Biopharmaceutical Manufacturing

Background:

• Current biopharmaceutical production relies on expression vectors with viral promoters (e.g., SV40, CMV) leading to high but potentially detrimental constitutive overexpression.
• Cell-cycle dependent and silencing-prone heterologous promoters contribute to heterogeneity in recombinant cell populations.
• Need for robust, endogenous gene regulatory elements to ensure stable and efficient foreign gene expression in CHO cells.

Purpose of the Study:

• To identify and isolate novel endogenous gene regulatory elements from Chinese hamster ovary (CHO) cells.
• To evaluate the potential of these elements in regulating foreign gene expression within recombinant CHO host cells.
• To develop a more stable and efficient system for biopharmaceutical production.

Main Methods:

• Construction of a genomic CHO library for comprehensive screening.
• Identification of target sequences using gene-specific amplification with primers targeting genes and vector sequences.
• Inverse PCR applied to fragmented and self-ligated genomic DNA to map flanking regions.
• Luciferase reporter assays to quantify expression levels of derived and mapped fragments.

Main Results:

• Successfully constructed a genomic library from CHO cells.
• Identified and isolated specific endogenous DNA sequences with potential gene regulatory functions.
• Demonstrated the ability of these sequences to influence reporter gene expression levels via luciferase assays.

Conclusions:

• Novel CHO endogenous gene regulatory elements capable of controlling foreign gene expression have been identified.
• These elements offer a promising alternative to traditional viral promoters for improved biopharmaceutical production.
• The findings contribute to the development of more stable and efficient recombinant CHO host cell lines.