SON (gene)

SON protein is a protein that in humans is encoded by the SON gene.

SON
Identifiers
Aliases	SON, BASS1, C21orf50, DBP-5, NREBP, SON3, SON DNA binding protein, TOKIMS, SON DNA and RNA binding protein
External IDs	OMIM: 182465; MGI: 98353; HomoloGene: 10551; GeneCards: SON; OMA:SON - orthologs
Gene location (Human) Chr. Chromosome 21 (human) Band 21q22.11 Start 33,543,038 bp End 33,577,481 bp
Gene location (Mouse) Chr. Chromosome 16 (mouse) Band 16 C3.3- C4|16 53.22 cM Start 91,444,394 bp End 91,476,109 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in pylorus tendon of biceps brachii cardia nipple trabecular bone renal medulla pericardium right uterine tube trigeminal ganglion seminal vesicula Top expressed in tunica media of zone of aorta neural layer of retina retinal pigment epithelium ciliary body vas deferens right lung lobe Rostral migratory stream efferent ductule crypt of lieberkuhn of small intestine maxillary prominence More reference expression data BioGPS More reference expression data
Gene ontology Molecular function RS domain binding protein binding RNA binding DNA binding nucleic acid binding Cellular component nuclear speck nucleus Biological process regulation of cell cycle cell cycle mRNA processing negative regulation of apoptotic process microtubule cytoskeleton organization RNA splicing regulation of mRNA splicing, via spliceosome mitotic cytokinesis regulation of RNA splicing Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 6651 20658 Ensembl ENSG00000159140 ENSMUSG00000022961 UniProt P18583 Q9QX47 RefSeq (mRNA) NM_001291411 NM_001291412 NM_003103 NM_032195 NM_138925 NM_138927 NM_019973 NM_178880 RefSeq (protein) NP_001278340 NP_001278341 NP_115571 NP_620305 NP_064357 NP_849211 Location (UCSC) Chr 21: 33.54 – 33.58 Mb Chr 16: 91.44 – 91.48 Mb PubMed search
Wikidata
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SON is the name that has been given to a large Ser/Arg (SR)-related protein, which is a splicing co-factor that contributes to an efficient splicing within cell cycle progression. It is also known as BASS1 (Bax antagonist selected in saccharomyces 1) or NRE-binding protein (Negative regulatory element-binding protein). The most common gene name of this splicing protein is SON, but C21orf50, DBP5, KIAA1019 and NREBP can also be used as synonyms.

The protein encoded by SON gene binds to a specific DNA sequence upstream of the upstream regulatory sequence of the core promoter and second enhancer of human hepatitis B virus (HBV). Through this binding, it represses HBV core promoter activity, transcription of HBV genes, and production of HBV virions. The protein shows sequence similarities with other DNA-binding structural proteins such as gallin, oncoproteins of the MYC family, and the oncoprotein MOS. It may also be involved in protecting cells from apoptosis and in pre-mRNA splicing. Mutation in SON gene is associated with ZTTK syndrome.

Structure

The sequence length of the SON protein consists in 2426 aminoacids and its sequence status is totally completed. Its molecular weight is 263,830 daltons (Da) and its domain contains 8 types of repeats which are distributed in 3 regions. This protein is mostly located in nuclear speckles. Its higher expression is seen in leukocyte and heart cells.

Splicing process

Location of the gene that encodes the SON protein.

SON protein is essential for maintaining the subnuclear organization of the factors that are processed in the nucleus highlighting its direct role in pre-mRNA splicing.

Splicing is the process through which pre-mRNA is transformed into mRNA. The pre-mRNA which has just been transcribed contains sequences called introns and exons. Introns are non-active nucleotide sequences that must be removed in order for the exons (active sequences) to be joined together forming mRNA. The controlled process of splicing takes place in the spliceosome, a complex that brings together pre-mRNA and a variety of binding proteins. These proteins together with the splicing factors (which are not found in the spliceosome) are in charge of recognizing the 5' ("donor") splice site, 3' ("acceptor") splice site, and branch point sequence within the intron. The SON protein is known to be one of these binding proteins.

Although there is a lack of knowledge about its exact splicing control in the progression of the cell cycle and it has remained largely unexplored, it’s certain that this splicing-associated protein is necessary for the maintenance of the embryonic stem cells because it influences the splicing of pluripotency regulators.

SON plays an important role in the mRNA processing. Nevertheless, this process is still a little uncertain and this is why in a future it will be interesting to understand how exactly this protein interacts with the spliceosomal complex, its exact molecular function in the context of splicing. Not only the SON protein interferes in the splicing but also makes complex mechanisms such as the RNA post-transcriptional to cooperate with the splicing-mRNA processing.

Human embryonic stem cells are able to undergo the process of differentiation into specific and relevant cells. To maintain the pluripotency of the embryonic stem cells, transcription factors and epigenetic modifiers play an important role despite the fact that little is known about the regulation of pluripotency throughout the process of splicing. The factor SON is identified as essential for the maintenance of this pluripotency. It is confirmed that SON regulates the splicing process of transcripts (RNAm) that will encode the gens that are going to regulate the pluripotency of the embryonic human cells.

Function

SON protein's intervention in the splicing process.

On the one hand, SON protein is required to maintain the genome stability in order to ensure an efficient RNA processing of affected genes. It also facilitates the interaction of SR proteins with RNA polymerase II and is required for processing of weak constitutive splice sites, having also strong implications in cancer and other human diseases.

On the other side, a deficiency or knockdown of SON protein causes various and severe defects in mitotic division arrangement, chromosome alignment and microtubule dynamics when spindle pole separation takes place.

But as we could read in the article called “SON protein regulates GATA-2 through transcriptional control of the microRNA 23a-27-24-a clúster”, SON protein has even more functions in the organism. It has been found that these proteins may regulate the hematopoietic cells differentiation. They have a specific job in hematopoietic process, which is based on activating other proteins called GATA. As these ones are finally activated, the cell differentiation starts normally.

Clinical significance

A recent study suggested that SON may be a novel therapeutic molecular target for pancreatic cancer as the results of a recent study show that this protein is very important as far as proliferation, survival and tumorigenicity of cancer cells are concerned. Specifically, these results revealed that the serine-arginine-rich protein involved in the RNA splicing process, could suppress pancreatic cell tumorigenicity.

The therapeutic implications of the SON gene within virus-host interactions, particularly in the context of viral infections, remain insufficiently defined. Although the SON gene is recognized for its engagement in diverse cellular processes like mRNA splicing, DNA repair, and cell cycle regulation, its precise involvement in the host's response to viral infections and its therapeutic applications remain ambiguous). Ongoing research is dedicated to unraveling the intricate interactions between host genes, including SON, and HIV-1. This pursuit aims to enhance our comprehension of the dynamics between viruses and hosts, with the potential to unveil novel targets for therapeutic interventions.

RNA Processing and viral replication

SON plays a crucial role in mRNA splicing, a vital process for gene expression. Certain viruses depend on the host's cellular machinery, including the splicing apparatus, for their replication. Disrupting host factors involved in RNA processing could potentially impede viral replication. Aberrations in splicing processes may lead to abnormal protein production and contribute to disease. Given SON's involvement in RNA processing, it emerges as a promising target for comprehending and treating conditions associated with splicing abnormalities.

Genetic and epigenetic approaches

In the event that SON is identified as a contributor to either promoting or inhibiting viral replication, there is potential for exploring genetic or epigenetic strategies. This could involve manipulating SON expression or activity to influence the viral life cycle.

Immunomodulation

Host factors also play a role in shaping the immune response to viral infections. If SON is implicated in pathways related to the immune system, modulating its activity could have implications for enhancing the host's capacity to control viral infections.

Further reading

• Mattioni T, Hume CR, Konigorski S, Hayes P, Osterweil Z, Lee JS (October 1992). "A cDNA clone for a novel nuclear protein with DNA binding activity". Chromosoma. 101 (10): 618–624. doi:10.1007/BF00360539. PMID 1424986. S2CID 23195894.
• Bliskovskiĭ VV, Berdichevskiĭ FB, Tkachenko AV, Belova ME, Chumankov IM (1992). "[Coding part of the son gene small transcript contains four areas of complete tandem repeats]". Molekuliarnaia Biologiia. 26 (4): 793–806. PMID 1435773.
• Bliskovskiĭ VV, Kirillov AV, Zakhar'ev VM, Chumankov IM (1992). "[The human son gene: the large and small transcripts contains various 5'-terminal sequences]". Molekuliarnaia Biologiia. 26 (4): 807–812. PMID 1435774.
• Tassone F, Cheng S, Gardiner K (December 1992). "Analysis of chromosome 21 yeast artificial chromosome (YAC) clones". American Journal of Human Genetics. 51 (6): 1251–1264. PMC 1682922. PMID 1463009.
• Chumakov IM, Berdichevskiĭ FB, Sokolova NV, Reznikov MV, Prasolov VS (1991). "[Identification of a protein product of a novel human gene SON and the biological effect upon administering a changed form of this gene into mammalian cells]". Molekuliarnaia Biologiia. 25 (3): 731–739. PMID 1944255.
• Berdichevskiĭ FB, Chumakov IM, Kiselev LL (1988). "[Decoding of the primary structure of the son3 region in human genome: identification of a new protein with unusual structure and homology with DNA-binding proteins]". Molekuliarnaia Biologiia. 22 (3): 794–801. PMID 3054499.
• Khan IM, Fisher RA, Johnson KJ, Bailey ME, Siciliano MJ, Kessling AM, et al. (January 1994). "The SON gene encodes a conserved DNA binding protein mapping to human chromosome 21". Annals of Human Genetics. 58 (1): 25–34. doi:10.1111/j.1469-1809.1994.tb00723.x. PMID 8031013. S2CID 31519119.
• Kikuno R, Nagase T, Ishikawa K, Hirosawa M, Miyajima N, Tanaka A, et al. (June 1999). "Prediction of the coding sequences of unidentified human genes. XIV. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro". DNA Research. 6 (3): 197–205. doi:10.1093/dnares/6.3.197. PMID 10470851.
• Greenhalf W, Lee J, Chaudhuri B (September 1999). "A selection system for human apoptosis inhibitors using yeast". Yeast. 15 (13): 1307–1321. doi:10.1002/(SICI)1097-0061(19990930)15:13<1307::AID-YEA455>3.0.CO;2-3. PMID 10509013. S2CID 30982094.
• Hattori M, Fujiyama A, Taylor TD, Watanabe H, Yada T, Park HS, et al. (May 2000). "The DNA sequence of human chromosome 21". Nature. 405 (6784): 311–319. Bibcode:2000Natur.405..311H. doi:10.1038/35012518. PMID 10830953.
• Wynn SL, Fisher RA, Pagel C, Price M, Liu QY, Khan IM, et al. (August 2000). "Organization and conservation of the GART/SON/DONSON locus in mouse and human genomes". Genomics. 68 (1): 57–62. doi:10.1006/geno.2000.6254. PMID 10950926.
• Sun CT, Lo WY, Wang IH, Lo YH, Shiou SR, Lai CK, Ting LP (June 2001). "Transcription repression of human hepatitis B virus genes by negative regulatory element-binding protein/SON". The Journal of Biological Chemistry. 276 (26): 24059–24067. doi:10.1074/jbc.M101330200. PMID 11306577.
• Reymond A, Friedli M, Henrichsen CN, Chapot F, Deutsch S, Ucla C, et al. (November 2001). "From PREDs and open reading frames to cDNA isolation: revisiting the human chromosome 21 transcription map". Genomics. 78 (1–2): 46–54. doi:10.1006/geno.2001.6640. PMID 11707072.
• Yi J, Kloeker S, Jensen CC, Bockholt S, Honda H, Hirai H, Beckerle MC (March 2002). "Members of the Zyxin family of LIM proteins interact with members of the p130Cas family of signal transducers". The Journal of Biological Chemistry. 277 (11): 9580–9589. doi:10.1074/jbc.M106922200. PMID 11782456.
• Casadei R, Strippoli P, D'Addabbo P, Canaider S, Lenzi L, Vitale L, et al. (December 2003). "mRNA 5' region sequence incompleteness: a potential source of systematic errors in translation initiation codon assignment in human mRNAs". Gene. 321: 185–193. doi:10.1016/S0378-1119(03)00835-7. hdl:11586/196824. PMID 14637006.
• Hillman RT, Green RE, Brenner SE (2005). "An unappreciated role for RNA surveillance". Genome Biology. 5 (2): R8. doi:10.1186/gb-2004-5-2-r8. PMC 395752. PMID 14759258.
• Colland F, Jacq X, Trouplin V, Mougin C, Groizeleau C, Hamburger A, et al. (July 2004). "Functional proteomics mapping of a human signaling pathway". Genome Research. 14 (7): 1324–1332. doi:10.1101/gr.2334104. PMC 442148. PMID 15231748.