Scientists in the Protein Expression Laboratory at NCI-Frederick (same NCI location as Frank and Sandra Ruscetti) have apparently made progress in accurately identifying XMRV proteins. This article is hyper-technical. I'm not in a position to evaluate it critically. I'm posting this for those more well versed in this field. It seems that they have dramatically increased their rate of success in identifying XMRV by switching the order in which they attempt to purify and express the proteins in their samples. Who even knew there was a Journal of Protein Expression and Purification? Anyone care to elaborate? Let me know if you need a copy of the full manuscript. It is nice (and reassuring) to see that interest in XMRV appears to be spreading across the range of biological sub-specialties. Protein Expr Purif. 2010 Dec 9. [Epub ahead of print] Purify First: Rapid Expression and Purification of Proteins from XMRV. Gillette WK, Esposito D, Taylor TE, Hopkins RF, Bagni RK, Hartley JL. Protein Expression Laboratory, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702. Abstract Purifying proteins from recombinant sources is often difficult, time-consuming, and costly. We have recently instituted a series of improvements in our protein purification pipeline that allows much more accurate choice of expression host and conditions and purification protocols. The key elements are parallel cloning, small scale parallel expression and lysate preparation, and small scale parallel protein purification. Compared to analyzing expression data only, results from multiple small scale protein purifications predict success at scale-up with greatly improved reliability. Using these new procedures we purified eight of nine proteins from xenotropic murine leukemia virus-related virus (XMRV) on the first attempt at large scale.