Ioannis Dragatsis


Faculty image

Associate Professor
Phone: 901-448-3615
Fax: 901-448-7126
Email: idragatsis@uthsc.edu
Full CV

Education

1989 B.S. University of Athens, Greece
1995 Ph.D. University of Athens, Greece

Research Interest

My laboratory is interested in studying the molecular basis of neurodegenerative diseases using Huntington's Disease (HD) as a model system. HD is an autosomal dominant disorder that affects 1 in 10,000 individuals. HD is characterized by chorea, rigidity and progressive dementia. Symptoms usually begin between the ages of 35 and 50 years, with death typically following 15 to 20 years later. HD is caused by the expansion of an unstable stretch of CAG triplet repeats within the coding region of the HD gene. Moreover the protein encoded by the HD gene, huntingtin, is a novel protein of unknown function.

We are using the mouse as a model organism. Inactivation of the mouse homologue of the HD gene results in embryonic lethality demonstrating that huntingtin is essential for early embryonic development. Conditional inactivation of the gene at later stages results in progressive neurodegeneration in the adult mouse, suggesting that huntingtin is also essential for neuronal survival.

Analysis of genetically engineered mice provides information in the context of the entire organism, throughout development and in adult organs, and complements in vitro analyses of normal and mutant huntingtin. In addition to providing important practical information regarding a devastating disorder, an analysis of the normal function of huntingtin and its interacting proteins can also provide important basic information regarding normal development and neuronal function in the brain.

Techniques Utilized:

  • Molecular Biology: DNA and RNA isolation, PCR, cloning, site-directed mutagenesis, sequencing, Southern and Northern analysis, RT-PCR analysis, RNase protection, in vitro transcription.
  • Biochemistry: SDS-Page, detection of proteins using immunoblotting and immunoprecipitation.
  • Cell Biology: Cell culture (mammalian cells and in particular fibroblasts and mouse embryonic stem cells (ES), transfection and electroporation of mammalian cells, immortalization of cell lines.
  • Histology: paraffin and frozen sectioning, immunohistochemistry, in-situ hybridisation, confocal microscopy. Skeleton preparation.
  • Mouse genetics: Generation of genetically engineered (transgenic, chimeric) mice. Embryo collection, microinjection and embryo transfer

Selected Publications

  1. Dragatsis I., Efstratiadis A. and Zeitlin S. (1998) Mouse mutant embryos lacking huntingtin are rescued from lethality by wild-type extraembryonic tissues. Development 125: 1529-1539.
  2. Metzler M., Helgason C.D., Dragatsis I., Zhang T., Gan L., Pineault N., Zeitlin S.O., Humphries R.K. and Hayden M.R. (2000) Huntingtin is required for normal hematopoiesis. Human Molecular Genetics 9: 387-394.
  3. Dragatsis I., Dietrich P. and Zeitlin S. (2000) Expression of the Huntingtin-associated protein 1 gene in the developing and adult mouse. Neuroscience Letters 282: 37-40.
  4. Dragatsis I. and Zeitlin S. (2000) CaMKIIalpha-Cre transgene expression and recombination patterns in the mouse brain. Genesis 26: 133-135.
  5. Dietrich P., Dragatsis I., Xuan S., Zeitlin S. and Efstratiadis A. (2000) Conditional mutagenesis in mice with heat shock promoter-driven cre transgenes. Mammalian  Genome 11: 196-205.
  6. Dragatsis I., Levine M.S. and Zeitlin S. (2000) Inactivation of Hdh in the brain and testis results in progressive neurodegeneration and sterility in mice. Nature Genetics 26: 300-306.
  7. Dragatsis I. and Zeitlin S. (2001) A method for the generation of conditional gene repair mutations in mice. Nucleic Acids Research 29: e10.
  8. Reiner A., Del Mar N., Meade C.A., Yang H., Dragatsis I., Zeitlin S. and Goldowitz D. (2001) Neurons lacking huntingtin differentially colonize brain and survive in chimeric mice. Journal of Neuroscience  21:7608-7619.