Ioannis Dragatsis, Ph.D.

IOANNIS DRAGATSIS, Ph.D.

Assistant Professor
Department of Physiology
Director, Transgenic/Knockout Core, Center for Genomics & Bioinformatics
The University of Tennessee College of Medicine

Address

The University of Tennessee Health Science Center
894 Union Avenue
Memphis, TN 38163
Tel: (901) 448-3615; Fax: (901) 448-7126;
Lab: 502 Nash Research Building

Education

Ph.D. Institution: University of Athens, Greece
Postdoctoral: Columbia University, College of Physicians and Surgeons, Department of Genetics and Development, New York, NY , USA

Research Interests

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.

Links

Physiology - Ioannis Dragatsis
Transgenic and Knockout Facility

Recent Publications

  • Zhang H, Das S, Li QZ, Dragatsis I, Repa J, Zeitlin S, Hajnóczky G, Bezprozvanny I. Elucidating a normal function of huntingtin by functional and microarray analysis of huntingtin-null mouse embryonic fibroblasts. BMC Neurosci. 2008 Apr 15;9:38. PMID: 18412970
  • Liu L, Geisert EE, Frankfurter A, Spano AJ, Jiang CX, Yue J, Dragatsis I, Goldowitz D. A transgenic mouse class-III beta tubulin reporter using yellow fluorescent protein. Genesis. 2007 Sep;45(9):560-9. PMID: 17868115
  • Baranova O, Miranda LF, Pichiule P, Dragatsis I, Johnson RS, Chavez JC. Neuron-specific inactivation of the hypoxia inducible factor 1 alpha increases brain injury in a mouse model of transient focal cerebral ischemia. J Neurosci. 2007 Jun 6;27(23):6320-32. PMID: 17554006
  • Zhang Y, Leavitt BR, van Raamsdonk JM, Dragatsis I, Goldowitz D, MacDonald ME, Hayden MR, Friedlander RM. Huntingtin inhibits caspase-3 activation. EMBO J. 2006 Dec 13;25(24):5896-906. Epub 2006 Nov 23. PMID: 17124493
  • McMinn JE, Liu SM, Liu H, Dragatsis I, Dietrich P, Ludwig T, Boozer CN, Chua SC Jr. Neuronal deletion of Lepr elicits diabesity in mice without affecting cold tolerance or fertility. Am J Physiol Endocrinol Metab. 2005 Sep;289(3):E403-11. Epub 2005 May 3. PMID: 15870101
  • Helton R, Cui J, Scheel JR, Ellison JA, Ames C, Gibson C, Blouw B, Ouyang L, Dragatsis I, Zeitlin S, Johnson RS, Lipton SA, Barlow C. Brain-specific knock-out of hypoxia-inducible factor-1alpha reduces rather than increases hypoxic-ischemic damage. J Neurosci. 2005 Apr 20;25(16):4099-107. Erratum in: J Neurosci. 2005 May 11;25(19):1 p following 4888. PMID: 15843612
view complete list of references (pubmed link)