Chromatin Human chromosomal DNA is packaged into a string of distinct protein-nucleic acid complexes, called chromatin structures, which are critical for gene regulation, genome stability, and protection against cancer. A chromatin structure is generally considered to belong one of two broad categories: euchromatin or heterochromatin. Euchromatin is permissive towards gene expression while heterochromatin structures are repressive. The cell utilizes "facultative heterochromatin" to turn gene expression off and "constitutive heterochromatin" to maintain genome stability. The mechanisms by which constitutive heterochromatin maintains genome stability are poorly understood. The Marahrens laboratory studies the role of heterochromatin in maintaining genome stability using knockout mice and ex vivo chromatin remodeling systems in conjunction chromatin immunoprecipitation and immunofluorescence imaging which monitor chromatin defects in response to mutations.
