Transcriptional Modulation by Nuclear Matrix Protein P130/MAT3 Associated with MAR/SAR
Various types of proteins are required for nuclear organization, which confers a variety of nuclear functions in eukaryotic cells. A set of proteins forms the chromosomal backbone (Paulson and Laemmli 1977) and different sets of proteins including chromatin-remodeling factors regulate the utilization of genetic code in chromosomal DNA (Boulikas 1995; Moazed 2001; Muchardt and Yaniv 2001). Eukaryotic chromosomes are topologically attached to the nuclear matrix (NM) or scaffold, a network of protein fibers referred to as the skeletal framework of the nucleus. The NM or scaffold is operationally defined as the residual structures that remain insoluble after extraction of nuclei with a high concentration of either salt or detergent. Several members of the group of proteins classified as components of the NM can directly bind to particular segments of chromosomal DNA. A DNA segment to which matrix and scaffold proteins can bind is termed a matrix or scaffold attachment region (MAR/SAR) (Cockerill and Garrard 1986; Gasser and Laemmli 1986; Cockerill et al. 1987; Jarman and Higgs 1988). One significant role of MAR/SARs that was revealed by structural analyses of the nucleus and chromosomes is the matrix- or scaffold-mediated stabilization of chromosomal structure. Chromosomal loops with an approximate length of ∼60 kilobases yield compact configurations of chromosomes.
KeywordsNuclear Matrix Chromosome Territory Nuclear Matrix Protein Protein MeCP2 Transcription Modulation
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