Disease relevance of SON

• Transcription repression of human hepatitis B virus genes by negative regulatory element-binding protein/SON [1].
• The endogenous NREBP protein is localized in the nucleus of human hepatoma HuH-7 cells [1].
• Overexpression of NREBP can also repress the transcription of HBV genes and the production of HBV virions in a transient transfection system that mimics the viral infection in vivo [1].
• In this study, a yeast one-hybrid screen for proteins that associate with the NRE led to the identification of the leukemia/lymphoma-related factor (LRF), a transcriptional repressor that contains a POZ (poxvirus zinc finger) domain, as an NRE-binding protein [2].
• These results suggested that the NREBP may mediate the NRE activity of the EICP0 promoter and may function in the coordinate expression of EHV-1 genes [3].

High impact information on SON

• As properly processed mRNPs translocate through the pore, certain mRNP proteins are removed, probably through the enzymatic action of the DEAD-box helicase Dbp5, which binds to Nup159 and Gle1, components of the cytoplasmic filaments of the NPC [4].
• Gle1 and the phosphoinositide IP6 activate Dbp5's ATPase activity in vitro and this could provide critical spatial regulation of Dbp5 activity in vivo [4].
• Dbp5 is present mainly in the cytoplasm and is enriched at the cytoplasmic side of nuclear pore complexes (NPCs), suggesting that it acts in the late part of mRNP export [5].
• The DEAD box RNA helicase Dbp5 is essential for nucleocytoplasmic transport of mRNA-protein (mRNP) complexes [5].
• Here, we describe the identification and functional characterization of the NRE-binding protein, called NRF (NF-kappaB-repressing factor), which abolishes the transcriptional activity of the bordering NF-kappaB- binding sites by a distance-independent mechanism [6].

Biological context of SON

• By polymerase chain reaction-assisted binding site selection assay, we determined that the consensus sequence for NREBP binding is GA(G/T)AN(C/G)(A/G)CC [1].
• The genomic locus of the NREBP/SON gene is composed of 13 exons and 12 introns [1].
• The phylogenetic conservation of DBP-5, the ubiquity of its expression, its nuclear localization, and its ability to bind DNA sequences, raise the possibility that DBP-5 may play a role in the organization of interphase chromatin and/or in transcriptional regulation [7].
• To extend our cDNA project for accumulating basic information on unidentified human genes, we newly determined the sequences of 100 cDNA clones from a set of size-fractionated human adult and fetal brain cDNA libraries, and predicted the coding sequences of the corresponding genes, named KIAA1019 to KIAA1118 [8].
• Body weight and other measures of obesity showed a positive relationship with systolic blood pressure (SBP), but not with diastolic (K5) blood pressure (DBP5) [9].

Anatomical context of SON

• Gel shift assays performed with mouse L-M, rabbit RK-13, and human HeLa cell nuclear extracts and gamma-(32)P-labeled wild-type and mutant NREs demonstrated that a ubiquitous nuclear protein(s) (NRE-binding protein, NREBP) binds specifically to a sequence (bp -193 to -183) in the NRE [3].

Other interactions of SON

• In this paper, we report for the first time that the immunoglobulin transcription factor 2B (ITF2B) encoded by transcription factor 4 (TCF4) gene is a NRE binding protein [10].

References