SAF-B protein couples transcription and pre-mRNA splicing to SAR/MAR elements.
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Nayler O, Stratling W, Bourquin JP, Stagljar I, Lindemann L, Jasper H, Hartmann AM, Fackelmayer FO, Ullrich A, Stamm S
SAF-B protein couples transcription and pre-mRNA splicing to SAR/MAR elements.
Nucleic Acids Res. 1998 Aug 1;26(15):3542-9.
- PubMed ID
- 9671816 [ View in PubMed]
- Abstract
Interphase chromatin is arranged into topologically separated domains comprising gene expression and replication units through genomic sequence elements, so-called MAR or SAR regions (for matrix- or scaffold-associating regions). S/MAR regions are located near the boundaries of actively transcribed genes and were shown to influence their activity. We show that scaffold attachment factor B (SAF-B), which specifically binds to S/MAR regions, interacts with RNA polymerase II (RNA pol II) and a subset of serine-/arginine-rich RNA processing factors (SR proteins). SAF-B localized to the nucleus in a speckled pattern that coincided with the distribution of the SR protein SC35. Furthermore, we show that overexpressed SAF-B induced an increase of the 10S splice product using an E1A reporter gene and repressed the activity of an S/MAR flanked CAT reporter gene construct in vivo . This indicates an association of SAF-B with SR proteins and components of the transcription machinery. Our results describe the coupling of a chromatin organizing S/MAR element with transcription and pre-mRNA processing components and we propose that SAF-B serves as a molecular base to assemble a 'transcriptosome complex' in the vicinity of actively transcribed genes.