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N-Myc

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MYCN
Identifiers
AliasesMYCN, MODED, N-myc, NMYC, ODED, bHLHe37, v-myc avian myelocytomatosis viral oncogene neuroblastoma derived homolog, MYCN proto-oncogene, bHLH transcription factor, MYCNsORF, MYCNsPEP
External IDsOMIM: 164840; MGI: 97357; HomoloGene: 3922; GeneCards: MYCN; OMA:MYCN - orthologs
Orthologs
SpeciesHumanMouse
Entrez

4613

18109

Ensembl

ENSG00000134323

ENSMUSG00000037169

UniProt

P04198

P03966

RefSeq (mRNA)

NM_005378
NM_001293228
NM_001293231
NM_001293233

NM_008709

RefSeq (protein)

NP_001280157
NP_001280160
NP_001280162
NP_005369

NP_032735

Location (UCSC)Chr 2: 15.94 – 15.95 MbChr 12: 12.99 – 12.99 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

N-myc proto-oncogene protein also known as N-Myc or basic helix-loop-helix protein 37 (bHLHe37), is a protein that in humans is encoded by the MYCN gene.

Function

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The MYCN gene is a member of the MYC family of transcription factors and encodes a protein with a basic helix-loop-helix (bHLH) domain. This protein is located in the cell nucleus and must dimerize with another bHLH protein in order to bind DNA.[5] N-Myc is highly expressed in the fetal brain and is critical for normal brain development.[6]

The MYCN gene has an antisense RNA, N-cym or MYCNOS, transcribed from the opposite strand which can be translated to form a protein product.[7] N-Myc and MYCNOS are co-regulated both in normal development and in tumor cells, so it is possible that the two transcripts are functionally related.[8] It has been shown that the antisense RNA encodes for a protein, named NCYM, that has originated de novo and is specific to human and chimpanzee. This NCYM protein inhibits GSK3b and thus prevents MYCN degradation. Transgenic mice that harbor human MYCN/NCYM pair often show neuroblastomas with distant metastasis, which are atypical for normal mice. Thus NCYM represents a rare example of a de novo gene that has acquired molecular function and plays a major role in oncogenesis.[9]

Clinical significance

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Amplification and overexpression of N-Myc can lead to tumorigenesis. Excess N-Myc is associated with a variety of tumors, most notably neuroblastomas where patients with amplification of the N-Myc gene tend to have poor outcomes.[10][11][12] MYCN can also be activated in neuroblastoma and other cancers through somatic mutation.[13] Intriguingly, recent genome-wide H3K27ac profiling in patient-derived NB samples revealed four distinct SE-driven epigenetic subtypes, characterized by their own and specific master regulatory networks. Three of them are named after the known clinical groups: MYCN-amplified, MYCN non-amplified high-risk, and MYCN non-amplified low-risk NBs, while the fourth displays cellular features which resemble multipotent Schwann cell precursors. Interestingly, the cyclin gene CCND1 was regulated through distinct and shared SEs in the different subtypes, and, more importantly, some tumors showed signals belonging to multiple epigenetic signatures, suggesting that the epigenetic landscape is likely to contribute to intratumoral heterogeneity. [14]

Interactions

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N-Myc has been shown to interact with MAX.[15][16]

N-Myc is also stabilized by aurora A which protects it from degradation.[17] Drugs that target this interaction are under development, and are designed to change the conformation of aurora A. Conformational change in Aurora A leads to release of N-Myc, which is then degraded in a ubiquitin-dependent manner.[18]

Being independent from MYCN/MAX interaction, MYCN is also a transcriptional co-regulator of p53 in MYCN-amplified neuroblastoma.[citation needed] MYCN alters transcription of p53 target genes which regulate apoptosis responses and DNA damage repair in cell cycle. This MYCN-p53 interaction is through exclusive binding of MYCN to C-terminal domains of tetrameric p53. As a post-translational modification, MYCN binding to C-terminal domains of tetrameric p53 impacts p53 promoter selectivity and interferes other cofactors binding to this region.[19]

See also

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References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000134323 – Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000037169 – Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ "Entrez Gene: MYCN v-myc myelocytomatosis viral related oncogene, neuroblastoma derived (avian)".
  6. ^ Knoepfler PS, Cheng PF, Eisenman RN (2002). "N-myc is essential during neurogenesis for the rapid expansion of progenitor cell populations and the inhibition of neuronal differentiation". Genes Dev. 16 (20): 2699–712. doi:10.1101/gad.1021202. PMC 187459. PMID 12381668.
  7. ^ Armstrong BC, Krystal GW (1992). "Isolation and characterization of complementary DNA for N-cym, a gene encoded by the DNA strand opposite to N-myc". Cell Growth Differ. 3 (6): 385–90. PMID 1419902.
  8. ^ "MYCN opposite strand/antisense RNA [Homo sapiens]". Entrez Gene Database. National Center for Biotechnology Information, U.S. National Library of Medicine.
  9. ^ Suenaga Y, Islam SM, Alagu J, Kaneko Y, Kato M, Tanaka Y, Kawana H, Hossain S, Matsumoto D, Yamamoto M, Shoji W, Itami M, Shibata T, Nakamura Y, Ohira M, Haraguchi S, Takatori A, Nakagawara A (2014). "NCYM, a Cis-Antisense Gene of MYCN, Encodes a De Novo Evolved Protein That Inhibits GSK3β Resulting in the Stabilization of MYCN in Human Neuroblastomas". PLOS Genetics. 10 (1): e1003996. doi:10.1371/journal.pgen.1003996. PMC 3879166. PMID 24391509.
  10. ^ Cheng JM, Hiemstra JL, Schneider SS, Naumova A, Cheung NK, Cohn SL, Diller L, Sapienza C, Brodeur GM (June 1993). "Preferential amplification of the paternal allele of the N-myc gene in human neuroblastomas". Nat. Genet. 4 (2): 191–4. doi:10.1038/ng0693-191. PMID 8102299. S2CID 1620573.
  11. ^ Emanuel BS, Balaban G, Boyd JP, Grossman A, Negishi M, Parmiter A, Glick MC (1985). "N-myc amplification in multiple homogeneously staining regions in two human neuroblastomas". Proc. Natl. Acad. Sci. U.S.A. 82 (11): 3736–40. Bibcode:1985PNAS...82.3736E. doi:10.1073/pnas.82.11.3736. PMC 397862. PMID 2582423.
  12. ^ Brodeur GM, Seeger RC, Schwab M, Varmus HE, Bishop JM (1984). "Amplification of N-myc in untreated human neuroblastomas correlates with advanced disease stage". Science. 224 (4653): 1121–4. Bibcode:1984Sci...224.1121B. doi:10.1126/science.6719137. PMID 6719137.
  13. ^ Pugh TJ, Morozova O, Attiyeh EF, Asgharzadeh S, Wei JS, Auclair D, et al. (March 2013). "The genetic landscape of high-risk neuroblastoma" (PDF). Nature Genetics. 45 (3): 279–84. doi:10.1038/ng.2529. PMC 3682833. PMID 23334666.
  14. ^ Ciaccio R, De Rosa P, Aloisi S, Viggiano M, Cimadom L, Zadran SK, Perini G, Milazzo G (November 2021). "Targeting Oncogenic Transcriptional Networks in Neuroblastoma: From N-Myc to Epigenetic Drugs". International Journal of Molecular Sciences. 22 (23): 12883. doi:10.3390/ijms222312883. PMC 8657550. PMID 34884690.
  15. ^ Blackwood EM, Eisenman RN (March 1991). "Max: a helix-loop-helix zipper protein that forms a sequence-specific DNA-binding complex with Myc". Science. 251 (4998): 1211–7. Bibcode:1991Sci...251.1211B. doi:10.1126/science.2006410. PMID 2006410.
  16. ^ FitzGerald MJ, Arsura M, Bellas RE, Yang W, Wu M, Chin L, Mann KK, DePinho RA, Sonenshein GE (April 1999). "Differential effects of the widely expressed dMax splice variant of Max on E-box vs initiator element-mediated regulation by c-Myc". Oncogene. 18 (15): 2489–98. doi:10.1038/sj.onc.1202611. PMID 10229200.
  17. ^ Otto T, Horn S, Brockmann M, Eilers U, Schüttrumpf L, Popov N, Kenney AM, Schulte JH, Beijersbergen R, Christiansen H, Berwanger B, Eilers M (January 2009). "Stabilization of N-Myc is a critical function of Aurora A in human neuroblastoma". Cancer Cell. 15 (1): 67–78. doi:10.1016/j.ccr.2008.12.005. PMID 19111882.
  18. ^ Gustafson WC, Meyerowitz JG, Nekritz EA, Chen J, Benes C, Charron E, Simonds EF, Seeger R, Matthay KK, Hertz NT, Eilers M, Shokat KM, Weiss WA (27 August 2014). "Drugging MYCN through an Allosteric Transition in Aurora Kinase A." Cancer Cell. 26 (3): 414–27. doi:10.1016/j.ccr.2014.07.015. PMC 4160413. PMID 25175806.
  19. ^ Gu B, Zhu WG (2012). "Surf the post-translational modification network of p53 regulation". International Journal of Biological Sciences. 8 (5): 672–84. doi:10.7150/ijbs.4283. PMC 3354625. PMID 22606048.

Further reading

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This article incorporates text from the United States National Library of Medicine, which is in the public domain.

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