Dr. David Coombs, Ph.D.
B.A. Dartmouth College 1967
Ph.D. University of California (Los Angeles)
Molecular Biology Institute, 1974
Summer, 1965. Under the direction of Dr. T.B. Roos, Dartmouth College, performed hepatectomies on adrenalectomized rats to establish link between adrenal secretion and liver regeneration.
Summer, 1966. Participant in NSF Undergraduate Research Program, Dartmouth College, Dr. A.P. Nelson, advisor. Demonstrated the existence of a hybrid birch (Betula cordifolia) which results from a cross of B. papyrifera (paper birch) and B. lutea (yellow birch).
Summer, 1967. Studies host-controlled restriction and modification of phage with Dr. B. Howard at UCLA.
1967-73. Dr. F.A. Eiserling, Graduate Advisor, UCLA. completed studies on phage T4 internal proteins, polyamine metabolism and arginine biosynthesis in infected and uninfected E. coli B, and the isolation and characterization of the "neck" proteins of T4. Specialized in electron microscopy, SDS PAGE, density gradient centrifugation, and both phage genetics and morphogenesis. Developed and patented a centrifuge tube piston fractionator.
1974-1977. Dr. G.D. Pearson, sponsor, Oregon State University. Studied adenovirus 2 DNA replication with the goal of elucidating the roles the inverted terminal redundancy and 55K dalton covalent protein complex present at each end of the linear chromosome. Developed a sensitive and reversible filter binding assay for the protein-DNA complex. Showed that the protein is attached to replicating, as well as completed chromosomes, strongly implicating the protein in the replication initiation) process. Protein-DNA covalent complexes were also discovered in several other eukaryotic systems, most notably HeLa cells. In HeLa, the proteins are found at long intervals (50,000 bp) and the binding sites are sensitive (55%) to digestion by single-strand specific nuclease Sl.
1978. Dr. C.E. Mathews, sponsor, Oregon State University. Visited Mathews' lab briefly to study DNA precursor synthesis and a T4 enzyme complex containing several DNA precursor enzymes which follows the replication fork.
1978-1979. Joined Agresearch Inc. of Los Angeles as director of production of a viral insecticide for douglas fir tussock moth (USDA contract). Gained a thorough knowledge of insect viruses, particularly of the polyhedrosis class, as well as firsthand experience in mass insect rearing techniques. Was solely responsible for the construction, financing and management of a large mass rearing facility. 4
The primary focus of my research has been the structure and assembly of large protein aggregates, specifically bacteriophage T4. We have identified several maverick head proteins as cleavage products of the major head species using 2D peptide mapping, and have been involved in a very fruitful investigation of the 3D structure of the baseplate using chemical cross-linking, 2D gel electrophoresis, antibody labeling, immunogold labeling and undecagold immunolabeling in collaboration with Dr. Hainfeld of the Brookhaven National Lab STEM facility on Long Island, N.Y.
This work continues as we expand our repertoire of baseplate protein- specific antibodies and should eventually lead to a complete 3D map of T4 baseplate proteins.
There have also been several productive collaborations with other Fredericton-based researchers including studies of a) the possible role of 7SK RNA in the regulation of oncogene transcription with Dr. M.O. Krause, b) plasmid-based pathogenic factors in the fish pathogen A. salmonicida with Dr. W.H. Lynch, and c) transport of viroid RNA in infected plant tissues with Dr. R. Singh at Agriculture Canada.
A recent addition to my laboratory's research focus involves the oncogenic human papillomavirus. Post-doc Dr. Kerry Ready is cloning the transforming E6 and E7 genes into a baculovirus expression vector so that we can raise antisera against the proteins and then study their intracellular distribution. This is an attempt to confirm their suspected DNA binding capability and their role in oncogenesis.
1966 NSF Undergraduate Research Award
1975-77 NIH Postdoctoral Fellowship
Coombs, D.H. 1974. The morphogenesis, structure, and protein composition of the head to tail attachment region of bacteriophage T4. Ph.D. Thesis, UCLA.