Chromosomal Proteins and Chromatin Function

Precise and specific interactions between chromosomal proteins and DNA are key elements for proper packaging of the DNA into chromatin, and are necessary for the orderly progression of most of the DNA-related activities such as transcription, replication, recombination and repair. Our aim is to understand the molecular mechanisms whereby specific chromosomal proteins affect various DNA-dependent activities in the context of chromatin. Specifically, we study the chromatin organization and cellular function of histones and HMG proteins. HMG proteins, the most abundant group of non histone nuclear proteins, serve as architectural elements which affect the structure of both the DNA and the chromatin fiber. Structural alterations caused by HMG proteins facilitate a variety of DNA-dependent processes occurring in the context of chromatin. Presently, we focus on the HMGN family, the only nuclear proteins that bind specifically to nucleosome cores, i.e. to the building block of the chromatin fiber. HMGN proteins unfold chromatin and facilitate access to the nucleosome. We are using a multidisciplinary approach which includes methodologies used in molecular biology, biochemistry, cell biology and immunochemistry, to study the structure of the proteins and their genes, the organization of the proteins in nucleosomes, their expression during the cell cycle and differentiation, the manner in which they assemble into the chromatin fiber, the pathway of their entry into the nucleus, their intranuclear trafficking, and their role in transcription and cellular differentiation. These studies are relevant to the understanding of molecular mechanisms regulating gene expression in the context of chromatin Our laboratory developed immunochemical approaches to study the organization of histones and non-histones in chromatin. These and other approaches we developed for studies on Histones and HMG proteins are applicable to the study of most nuclear proteins.

chromatin unfolding...  |  Intracellular Trafficking...  |   Organization of HMG...
New HMG...  |  Linker Histone...  |  Modifications...  |  Development...

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Last revised on March 20, 2003 by Linda G. Byrd, Ph.D.

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