Personal Information and Interests

Education:
B.Eng. Environmental Engineering
National University of Singapore, Singapore, 2002

M.Sc. (Molecular Engineering in Biological and Chemical Systems
Singapore-MIT Alliance, Singapore, 2003

Academic Interests

Research Interests: Variability of Transgene Stability and Productivity in Chinese Hamster Ovary (CHO) Cells
Thesis Advisors: Daniel I. C. Wang and Miranda G. S. Yap

Research Description

In the field of biologics production, productivity and stability of the transfected gene of interest are two very important attributes that dictate if a production process is viable. To further understand and improve these two traits, we would need to further our understanding of the factors affecting them. These would include integration site of the gene, gene copy number, cell phenotypic variation and cell environment. As these factors play different parts in the development process, they lead to variable productivity and stability of the transfected gene between clones, the well-known phenomenon of "clonal variation". A study of this phenomenon and how the various factors contribute to it will thus shed light on strategies to improve productivity and stability in the production cell line.

Of the four factors, the site of gene integration appears to be one of the most important. During the amplification process in a typical cell development process of CHO cells, it is known that the amplified sequence (amplicon) is much larger than the transfected vector, suggesting that it would include the flanking genomic DNA sequences. This outlines the possible importance of the initial integration site in the development process. Presence of other factors in genomic sequences, such as enhancers, Locus Control Regions (LCRs) and repressors, also points to the importance of integration sites in affecting the expression of transfected genes in stable clones.

A study how different integration sites affect the productivity and stability of transfected genes in the development process is thus proposed. For the study to be more industrially relevant, the Chinese Hamster Ovary dhfr-deficient cell line, CHO-DG44, is chosen as the model system.