David J Segal, PhD

Associate Professor UC Davis Genome Center Department of Pharmacology School of Medicine 4513 GBSF 451 E. Health Sciences Drive Davis CA 95616 email:djsegal@ucdavis.edu phone: (530) 754-9134

Bio / Research:

Therapeutics for the Genome
How can we use the information in the human genome to improve human health? Our lab is developing DNA-recognition tools for use in functional genomics and gene therapy.

The Cys2-His2 class of zinc fingers are one of nature's favorite structural motifs. This is reflected in the fact that 4,500 zinc finger domains are encoded in our genome, more by far than any other type of protein fold. Our studies try to understand the purpose of these domains, learn how they accomplish their function, then try to use their abilities to create new tools that benefit human health and biological studies.

Zinc Fingers in Nature
What are all those zinc finger domains doing? Using the combined approaches of biochemistry, X-ray crystallography, computer modeling, and bioinformatics, we are revealing nature's purpose for encoding 4,500 zinc finger domains into our genome. Many transcription factors use zinc fingers to bind DNA, RNA, or other proteins. Understanding the rules of recognition would help us to predict the function of many uncharacterized proteins in the genome. It would also enable us to build better sequence specific therapeutics and tools.

Engineering DNA-Binding Proteins
Each DNA-binding ZnFn domain recognizes about 3 bp of DNA. In previous work, randomization and phage display selection were used to generate domains that could recognize new 3 bp target sites. These modified domains could then be assembled in any order to create new DNA-binding proteins to virtually any desired DNA binding site. Using this technology, we can now create custom DNA-binding proteins in a few hours using PCR. A 6 ZnFn protein should provide enough specificity to bind a unique site in the human genome. Typical affinity is <1 nM.

Methods to Detect Novel Double Stranded DNA
We are developing diagnostic tools, using a process we call "SEER" (Sequence-Enabled Enzyme Reactivation), that can scan the DNA inside a living cell and produce a fluorescent signal when a particular sequence is detected.

Repairing Genomes with Targeted Endonucleases
By making carefully targeted double-strand breaks in chromosomes, we can engineer insertions, deletions, and genomic rearrangements. For example, we are designing targeted endonuclease to seek and destroy the integrated HIV virus within cells. Other projects aim to repair genetic diseases at the DNA level through targeted homologous recombination.

Education:
BS, Cornell University; Ithaca, NY, 1989, Biology
PhD, University of Utah; Salt Lake City, UT, 1996, Biochemistry
PD, Scripps Research Institute; La Jolla, CA, 2000, Molecular Biology

Honors, Awards
1998, Scripps Society of Fellows, Fall Symposium Lecture Award

Publications