Genomic exploration on Chinese hamster ovary cells

Industrially important recombinant CHO cell clones carry many desirable phenotypic traits that differentiate them from the parental clone. The molecular basis for these traits at the genomic level is not well understood. A better understanding of key genetic alterations related to these traits will greatly facilitate the development of new cell lines and new processes. To advance this goal, we are constructing a CHO cDNA microarray. A phage library was constructed using mRNA pooled from different CHO clones under different cultivation conditions. Over four thousand sequences have been randomly isolated and sequenced. A cDNA microarray based on these sequences was constructed and used in gene expression studies. The differentially expressed genes identified by the CHO cDNA microarray were compared to those observed in cross-species hybridization to mouse cDNA microarrays. Sequence comparison with known mouse genes indicates only a moderate degree of homology. The results represent a significant step toward large-scale gene expression profiling for industrial mammalian cell culture processes.