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Critical Reviews™ in Eukaryotic Gene Expression
Fator do impacto: 1.841 FI de cinco anos: 1.927 SJR: 0.649 SNIP: 0.516 CiteScore™: 1.96

ISSN Imprimir: 1045-4403
ISSN On-line: 2162-6502

Critical Reviews™ in Eukaryotic Gene Expression

DOI: 10.1615/CritRevEukarGeneExpr.v6.i2-3.80
pages 271-283

Interrelationships between Nuclear Structure and Ligand-Activated Intracellular Receptors

Mary F. Ruh
Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104
Robert Dunn, II
Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104
Thomas S. Ruh
Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104

RESUMO

The role of ligand-activated intracellular receptors in activation of gene expression most probably involves a multistep process that requires alteration in chromatin structure. Results of studies with members of the steroid hormone receptor superfamily as well as the ligand-activated member of the basic region/helix-loop-helix family of transcriptional activators suggests that two different nuclear structures and their associated nuclear proteins are important in the initial stages of gene activation: the nuclear matrix and nucleosomes. Cell- and tissue-specific nuclear matrix proteins and the variant and modified histones appear to be important for tissue and species specificity of ligand-induced responses. Because the function of a receptor may be limited in vivo by promoter and transcription factor accessibility, the various roles of nuclear ligand-receptor complexes may involve interaction with nuclear matrix proteins and/or nucleosomes. Tissue-specific structural nuclear proteins could control the conformation (looping through matrix attachment regions) of the DNA and unwinding or rearrangement of nucleosomes, thus providing specificity to the expression of certain genes. Modulation of cooperative elements required for gene activation may involve association of the gene promoter with the nuclear matrix together with the presence of nucleosomes. Thus, the series of events involved in ligand-receptor activation of genes requires alterations in chromatin structure, which allow access of the receptor complex to elements within the gene.