Drosophila SAF-B links the nuclear matrix, chromosomes, and transcriptional activity

• Published in: PloS one Vol. 5; no. 4; p. e10248
• Main Authors: Alfonso-Parra, Catalina, Maggert, Keith A
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 20.04.2010; Public Library of Science (PLoS)
• Subjects: Animals; Attachment; Binding proteins; Breast cancer; Cell Biology/Gene Expression; Cell Biology/Nuclear Structure and Function; Cell culture; Chromatin; Chromosomes; Chromosomes - metabolism; Compartments; Deoxyribonucleic acid; DNA; DNA - metabolism; Drosophila; Drosophila Proteins - metabolism; Gene expression; Genes; Genetic aspects; Genetics and Genomics/Nuclear Structure and Function; Genomes; Glands; Homology; Humans; Insects; Matrix Attachment Regions; Nuclear Matrix - chemistry; Nuclear Matrix - metabolism; Nuclear Matrix-Associated Proteins - metabolism; Nuclei; Nuclei (cytology); Protein Binding; Protein interaction; Proteins; Ribonucleic acid; RNA; RNA - metabolism; RNA polymerase; Salivary glands; Sequence Homology, Amino Acid; Transcription; Transcription (Genetics); Transcription factors; Transcriptional Activation; Texas
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0010248

Induction of gene expression is correlated with alterations in nuclear organization, including proximity to other active genes, to the nuclear cortex, and to cytologically distinct domains of the nucleus. Chromosomes are tethered to the insoluble nuclear scaffold/matrix through interaction with Scaffold/Matrix Attachment Region (SAR/MAR) binding proteins. Identification and characterization of proteins involved in establishing or maintaining chromosome-scaffold interactions is necessary to understand how the nucleus is organized and how dynamic changes in attachment are correlated with alterations in gene expression. We identified and characterized one such scaffold attachment factor, a Drosophila homolog of mammalian SAF-B. The large nuclei and chromosomes of Drosophila have allowed us to show that SAF-B inhabits distinct subnuclear compartments, forms weblike continua in nuclei of salivary glands, and interacts with discrete chromosomal loci in interphase nuclei. These interactions appear mediated either by DNA-protein interactions, or through RNA-protein interactions that can be altered during changes in gene expression programs. Extraction of soluble nuclear proteins and DNA leaves SAF-B intact, showing that this scaffold/matrix-attachment protein is a durable component of the nuclear matrix. Together, we have shown that SAF-B links the nuclear scaffold, chromosomes, and transcriptional activity.