Our Science

Susan M. Janicki, Ph.D.

Susan M. Janicki, Ph.D.

  • Associate Professor, Molecular and Cellular Oncogenesis Program
  • Scientific Director, Imaging Facility
  • 215-495-6850, Office
  • 215-495-6851, Lab

The Janicki laboratory is developing and using technologies to study transcriptional and epigenetic regulatory mechanisms in single living mammalian cells.  For a gene to be expressed, the functions of multiple molecular machines must be coordinated at the site of transcription.  To understand the role of nuclear organization in transcription, it is necessary to visualize the dynamic interactions of regulatory factors with chromatin and RNA.  

It is currently possible to localize individual transcription sites in single living mammalian cells by engineering genes to include sequence elements that permit the visualization of nucleic acids in real time.  Upon stable integration, these transgenes form chromatinized arrays, which can be imaged during activation to obtain high-resolution quantitative information about transcriptional dynamics.  Modeling can suggest new hypotheses about gene regulation, which can be tested both in the single-cell imaging system and at endogenous genes.  This gene-specific imaging strategy has the potential to reveal regulatory mechanisms, which would be difficult to imagine outside of single living cells. 

Dr. Janicki joined The Wistar Institute in 2005 after finishing her postdoctoral fellowship at Cold Spring Harbor Laboratory in New York. She received her bachelor’s degree in biology and English from Tufts University in Massachusetts in 1993, and her Ph.D. from the University of Maryland in Baltimore in 1999. In 2005, Janicki received the prestigious Beckman Young Investigator Award and in 2007 the Basil O'Connor Starter Scholar Research Award from the March of Dimes Foundation.

Selected Publications

1.    Newhart A and Janicki SM. Seeing is Believing: Visualizing Transcriptional Dynamics in Single Cells. (2013) Journal of Cellular Physiology. [Aug 8; Epub ahead of print] PMID: 23929405

2.    Newhart A, Rafalska-Metcalf IU, Yang T, Joo LM, Powers SL, Kossenkov AV, Lopez-Jones M, Singer RH, Showe LC, Skordalakes E, and Janicki SM. Single-cell analysis of RNA-mediated histone H3.3 recruitment to a cytomegalovirus promoter-regulated transcription site. (2013) Journal of Biological Chemistry. July 5;288(27):19882-99. Epub 2013 May 20. PMID: 23689370

3.    Newhart A, Negorev DG, Rafalska-Metcalf IU, Yang T, Maul GG and Janicki SM.  Sp100A promotes chromatin decondensation at a CMV-promoter regulated transcription site. (2013) Molecular Biology of the Cell. May;24(9):1454-68. Epub 2013 March 13. PMID: 23485562

4.    Rafalska-Metcalf IU and Janicki SM. (2013) Preparation of Cell Lines for Single-Cell Analysis of Transcriptional Activation Dynamics. In: Gene Regulation: Methods and Protocols. Minou Bina, editor. Humana Press, New York. 977:249-58. PMID: 23436368

5.    Newhart A, Rafalska-Metcalf IU, Yang T, Negorev DG, and Janicki SM.  Single cell analysis of Daxx and ATRX-dependent transcriptional repression. (2012) Journal of Cell Science. Nov 15;125(Pt 22):5489-501. Epub 2012 Sep 12. PMID: 22976303

6     Rafalska-Metcalf IU, Powers SL, Joo LM, LeRoy G, Janicki, SM., Single cell analysis of transcriptional activation dynamics., PLoS One. 2010 Apr 21;5(4):e10272., 20422051