A two-dimensional protein map of Chinese hamster ovary cells

Chinese hamster ovary (CHO) cells are used extensively for the expression o f biopharmaceutical protein products. As part of our effort to better under stand CHO cell physiology and protein expression changes caused by modified culture conditions, we have begun to map CHO cell polypeptides. A parental cell line reference map was established using two-dimensional gel electrop horesis with immobilized pH gradients (pH 3-10) in the first dimension and a linear acrylamide gradient (9-18%T) in the second dimension. The map is c omposed of over 1000 silver-stained protein spots. Protein identification i s proceeding using a combination of immunostaining, NH2-terminal sequencing , and mass spectrometric analyses. Among the proteins so far identified are glucose-regulated protein 78 (GRP78), protein disulfide isomerase (PDI), g alectin-1, and several heat-shock proteins. The goal is to generate a datab ase which emphasizes those proteins most relevant to the use of CHO cells a s a host for recombinant protein expression.