Frederick S. Gimble
Associate Professor of Biochemistry
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Area |
Protein-DNA interactions and protein engineering of homing endonucleases |
| Office
| BCHM 315 |
| Phone
| (765) 494-1653 |
| Email
| fgimble@purdue.edu |
| Degree |
Ph.D. Mass. Inst. of Technology, 1987 |
The sequence of the human genome will help identify genetic mutations that cause disease, and a central goal in the post-genomic era will be to develop tools to correct these errors. The repair of complex genomes requires having reagents available that 1) are capable of locating a specific sequence from among several hundred megabases of non-specific DNA and 2) are able to catalyze specific molecular modifications of the DNA that either initiate an endogenous repair pathway or effect repair directly.
Our laboratory has focused on designing and engineering homing endonucleases with novel functions that have the potential to facilitate DNA repair and other molecular processes. Homing endonucleases are encoded by mobile DNA elements that propagate between individuals within a population by “homing,” and between species through lateral transmission. These enzymes initiate homing by introducing a double-strand break at a single genomic target sequence situated within a cognate allele that lacks the mobile element. A long term goal of our group is to harness the extreme DNA sequence specificity of homing endonucleases to catalyze specified events at targeted genomic loci.
Several projects in the laboratory involve the rational design of the PI-SceI and I-SceI homing endonucleases from the yeast Saccharomyces cerevisiae using their available X-ray crystal structures. One goal is to introduce molecular switches into these enzymes that are activated by small molecule ligands or other stimuli in order to restrict their endonuclease activities to specific times in development or to targeted cells. A second objective is to tailor homing enzymes to recognize specific DNA sequences by developing methods that alter their target specificity. As a first step towards this goal, we selected variants of PI-SceI from a combinatorial protein library with marked shifts in their DNA-binding specificity by using a bacterial two-hybrid selection strategy. Finally, our laboratory studies enzymes related to PI-SceI and I-SceI that recognize different DNA targets in order to elucidate how alternate specificities evolve in nature.
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