Thursday, August 18, 2011

Nextera technology enables complete sequencing of the CHO cell genome

Chinese hamster ovary (CHO) cells are a workhorse in the production of therapeutic proteins. In a recent publication, Xu et al. report the complete sequencing of the CHO-K1 genome. Using the Nextera™ DNA Sample Prep Kit and the Illumina® HiSeq 2000 sequencer, the researchers at BGI-Shenzen and other institutions generated a draft sequence of approximately 2.45 Gb with 24,383 predicted genes. They report these results as a means of studying glycosylation and viral susceptibility, in an attempt to understand the divergence of genomic sequence information. Even among clones of CHO cells containing engineered or other therapeutic proteins, DNA translocations/rearrangements can occur. Prior to generating this draft sequence, the main tool for analyzing genome-scale changes has largely been limited to the use of expressed sequence tags (ESTs). The study describes how the availability of the CHO genome assists in understanding how protein glycosylation and viral susceptibility affect yields and the quality of production of therapeutic proteins. Based on these insights, the researchers expect enhanced application of CHO cell engineering for protein manufacturing.

ResearchBlogging.orgXu, X. et al. (2011). The genomic sequence of the Chinese hamster ovary (CHO)-K1 cell line Nature Biotechnology, 29 (8), 735-741 DOI: 10.1038/nbt.1932

Thursday, August 4, 2011

Fosmid libraries aid in identifying a novel lipase

The CopyControl™ Fosmid Library Production Kit remains a key tool in the discovery and sourcing of novel, useful enzymes. In a recent publication, Glogauer et al. identified a novel lipase gene from a fosmid metagenomic library constructed with "prokaryotic-enriched" DNA from fat-contaminated soil collected from a wastewater treatment plant. The library, containing over 500,000 unique clones, revealed esterase activity in 32 of the library member clones after screening on agar plates containing 1% tricaprylin, or 1% triolein (denoting the presence of true lipases). One of these clones produced a novel lipase enzyme that the authors believe will be a useful tool in biocatalytic processes.

The researchers state that the novel lipase possesses “high specific activity against long-chain triacylglycerols, activity and stability over a wide range of pH values, good thermal stability, and stability in water-miscible organic solvents and at high salt concentrations.”

Thus, even with the growth of high-throughput sequencing technologies, CopyControl fosmid libraries continue to assist in the discovery of novel activities in metagenomic populations that may not be possible in high-copy-number cloning procedures.

ResearchBlogging.orgGlogauer, A. et al. (2011). Identification and characterization of a new true lipase isolated through metagenomic approach Microbial Cell Factories, 10 (1) DOI: 10.1186/1475-2859-10-54