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Expert is internationally known for his contributions to the fields of biochemistry and molecular biology. He has worked in this area since 1964, generally in purifying enzymes involved in RNA synthesis, characterizing the structure and function of enzymes, and studying protein-protein and protein-DNA interactions.

His lab studies RNA polymerases and transcription factors from bacteria (especially E. coli) and from eukaryotes including wheat, yeast, calf thymus, and human cells. He discovered the complex subunit structure of E. coli RNA polymerase and the initiation factor, sigma-70, responsible for specific RNA synthesis (transcription). He also studies the mechanism of action of the phytotoxin tagetitoxin in inhibiting RNA polymerase.

Expert teaches a 28-lecture course at the Employer at Madison and a two week lab course at Cold Spring Harbor. He organized the Keystone Symposia on protein purification in 1986 and 1992. He has developed the use of polyethyleneimine precipitation as an important step in clarifying extracts and fractionating proteins. He has helped popularize the use of glycerol and dithiothrietol as protein stabilization agents.

As an early user of polyacrylamide gel electrophoresis (PAGE) and SDS-PAGE, he developed techniques for improving staining and quantitation of protein in gels. He dramatically improved the efficiency of eluting microgram amounts of enzymes from SDS gels, removal of SDS, and renaturation of active enzymes.

Since a sabbatical in 1983-84 with a medical diagnostic company, Expert has been very active in producing MAbs as reagents to aid in his biochemical studies. He has developed methods for rapid epitope-mapping. He has recently developed and patented a method for screening for rare MAbs ideal for immunoaffinity chromatography. These "polyol-responsive" MAb columns bind enzymes tightly but release under very gentle conditions of salt and polyol (glycerol, ethylene glycol, propylene glycol). This allows rapid immunoaffinity purification of labile enzymes.

He has considerable experience isolating enzymes from natural sources such as bacterial, yeast, wheat germ, and mammalian cell extracts. He is also very experienced at overproducing enzymes expressed from genes cloned into E. coli, solubilizing insoluble enzymes found in inclusion bodies, and refolding to yield active enzymes.

Expert has focused his career on understanding the RNA synthesis or transcription machinery. This includes RNA polymerases and transcription factors from prokaryote (mainly E. coli) and eukaryotes (wheat, yeast, calf, human). His work has involved purification, subunit characterization, immunochemical analysis, cloning and overproducing subunits, and protein-protein crosslinking.

In an area of secondary expertise, he has used heterobifunctional crosslinking reagents to determine where on RNA polymerase certain RNA polymerase-binding transcription factors are binding and thus to infer adjacency and subunit architecture.

He has used monoclonal antibodies to aid in biochemical studies of enzymes. He has developed several new ways of epitope mapping that are faster and easier than traditional protein chemical approaches.


He acted as expert witness in three biotechnology-related patent cases, in the area of protein biochemistry. He is a member of the Scientific Advisory Board for a local monoclonal antibody production company. He has consulted for several investment companies in the areas of biotechnology and technology evaluation. He has on numerous occasions consulted with biotechnology companies in the area of protein purification.