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Jennifer Ocbo, Don Chen's Lab, UMDNJ

Beginning from September 2004, I have been working as an undergraduate member of Dr. J. Don Chen’s research lab in the Department of Pharmacology for UMDNJ – RWJMS.  The main focus of the lab is to gain a mechanistic understanding of gene regulation at the level of transcription with emphasis on understanding the transcription factors that activate or repress a gene.  Factors of interest are nuclear hormone receptors whose transcriptional activity depends on the binding of lipophilic ligands, thereby in control of the biological processes of cell differentiation, development, and homeostasis.   Through obtaining a better understanding of the mechanisms of nuclear receptors, we may be able to further elucidate their role in cancers and diseases, and possibly seek out new methods of curing and preventing such disorders.

Many techniques utilizing molecular biology have been employed to study the mechanics of proteins involved in transcriptional regulation.  A different approach was designed by my lab which incorporates the use of RNA interference and its production of short hairpin RNAs to silence a targeted protein—in my case—the enhanced green fluorescent protein (EGFP).  EGFP was fused to the corepressor protein Tetracyclin (TetR) to make the fusion protein EGFP-TetR.  Generally, the transcription of EGFP-TetR results in a repressor protein that emits a green fluorescence throughout the cell.  My lab will apply the drug Doxycyclin (Dox) to the EGFP-TetR fusion protein to have Dox bind to the repressors and activate transcription of shEGFP and EGFP-TetR.  The resulting short hairpin RNAs specific to EGFP anneal to the transcript for the fusion protein and is consequently degraded by the cell.  If silencing of EGFP can result in decreased protein production and visual fluorescence, then hypothetically, EGFP’s fusion to a targeted corepressor or coactivator could result in its degradation as well.  A successful inducible system could result in further incorporation with associated silencing of other proteins of interest such as SMRT or RAC3.  The implication of this project, if successful, would be the establishment of an innovative manner of silencing protein transcription.  This would be of obvious use in many medical and biochemical applications.

References:

1. Chen, J. Don, Hui Li.  Coactivation and Corepression in Transcriptional Regulation by Steroid/Nuclear Hormone Receptors. Critical Reviews in Eukaryotic Gene Expression. 1998; 8(2):169-190.

1. Rubinson, Douglas A., Christopher P. Dillon, Adam V. Kwiatkowski, Claudia Sievers, Lili Yang, Johnny Kopinja, Mingdi Zhang, Michael T. McManus, Frank B. Gertler, Martin L. Scott, Luk Van Parijs.  A lentivirus-based system to functionally silence genes in primary mammalian cells, stem cells, and transgenic mice by RNA interference.  Nature Genetics. 2003, Mar; 33:401-406.

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