U.S. Department of Health and Human Services
Orna Cohen-Fix

 Contact Info

Tel: 301-594-2184
Email: ornacf@helix.nih.gov

 Select Experience

  • Adjunct ProfessorJohns Hopkins University2011–Present
  • Directorthe NIH/Johns Hopkins University Graduate Partnership Program, NIH2008–present
  • Senior Investigator and Section ChiefNIDDK, NIH2005–Present
  • Tenure-Track InvestigatorNIDDK, NIH1998–2005
  • Postdoctoral FellowThe Carnegie Institution of Washington1994–1998
  • Ph.D.Weizmann Institute of Science1994
  • M.S.Weizmann Institute of Science1989
  • B.A.Tel-Aviv University1986

 Related Links


    • Cell Biology/Cell Signaling

    ​Research Images

    Images or videos appear below. Clicking images or videos provides an expanded view.

    Nuclei of wild type and spo7∆ cellsWild type budding yeast cells (left panel) typically have round nuclei containing chromosomes (in blue) and a crescent shaped nucleolus (in green).  In contrast, spo7∆ mutant cells (right panel) have a nuclear protrusion at the site of the nucleolus.Nuclei of wild type and spo7∆ cellsEnlarge
    Nuclei of cells arrested in mitosisBudding yeast cells arrested in mitosis form a nuclear envelope projection adjacent to the nucleolus.  Shown are two cells arrested in mitosis by nocodazole treatment, which depolymerizes microtubules.  The cells express a nuclear protein (green) and a nucleolar marker (red, appears orange due to overlap with GFP).Nuclei of cells arrested in mitosisEnlarge
    A model for how the constant nuclear/cell volume can affect nuclear shapeIn yeast, and possibly other cells, there is a constant ratio between nuclear and cell volume.  If nuclear surface area increases the nucleus could expand, increasing its volume or the nuclear envelope could form protrusions and invaginations.  We propose that the latter happens to maintain a constant nuclear/cell volume ratio.A model for how the constant nuclear/cell volume can affect nuclear shapeEnlarge
    A mitotic nucleus in 3 D
    Nucleus of an arl1 spo7 mutant