Dataset Information

The MYCN oncoprotein is an RNA-binding protein that promotes nascent RNA turnover via the NEXT targeting complex of the nuclear exosome

ABSTRACT: The MYCN oncoprotein forms a DNA-binding heterodimer with its partner protein MAX. MYCN-driven tumor cells depend on the nuclear exosome, a 3`-5` RNA exonuclease complex, to progress through S phase. Here we show that MYCN forms stable high molecular weight complexes with the nuclear exosome and additional RNA-binding proteins. Enhanced cross-linking and immunoprecipitation (eCLIP) experiments reveal that MYCN binds to thousands of sites on RNA, mainly localized in introns. MYCN directly binds RNA with a preference for UG-rich sequences via a short, highly conserved sequence motif termed MycBox I. Upon exosome inhibition, MYCN relocalizes globally from promoters to intronic RNAs; at promoters, MYCN is then replaced by the repressive MXD6 (MNT) protein, leading to the recruitment of histone deacetylase complexes and inhibition of MYCN-dependent transcription. MYCN is tightly associated with the exosome targeting complex NEXT and promotes the degradation of non-polyadenylated RNA at its bound introns. Our data demonstrate that MYCN is an RNA-binding protein that controls nascent RNA turnover and argue that the competition between RNA- and DNA-bound states of MYCN links the dynamics of the MYCN/MAX/MXD network to the completion of mRNA processing.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Permanent Cell Line Cell, Cell Culture

DISEASE(S): Neuroblastoma

SUBMITTER: Petra Beli

LAB HEAD: Petra Beli

PROVIDER: PXD044446 | Pride | 2024-07-18

REPOSITORIES: Pride

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	20220315_SFB1_PBE_IM_LFQ_Eilers_Glycerol_R1_IgG_1.raw	Raw
	20220315_SFB1_PBE_IM_LFQ_Eilers_Glycerol_R1_IgG_2.raw	Raw
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	20220315_SFB1_PBE_IM_LFQ_Eilers_Glycerol_R1_IgG_4.raw	Raw
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The MYCN oncoprotein is an RNA-binding accessory factor of the nuclear exosome targeting complex.

Papadopoulos Dimitrios D Ha Stefanie Anh SA Fleischhauer Daniel D Uhl Leonie L Russell Timothy J TJ Mikicic Ivan I Schneider Katharina K Brem Annika A Valanju Omkar Rajendra OR Cossa Giacomo G Gallant Peter P Schuelein-Voelk Christina C Maric Hans Michael HM Beli Petra P Büchel Gabriele G Vos Seychelle M SM Eilers Martin M

Molecular cell 20240503 11

The MYCN oncoprotein binds active promoters in a heterodimer with its partner protein MAX. MYCN also interacts with the nuclear exosome, a 3'-5' exoribonuclease complex, suggesting a function in RNA metabolism. Here, we show that MYCN forms stable high-molecular-weight complexes with the exosome and multiple RNA-binding proteins. MYCN binds RNA in vitro and in cells via a conserved sequence termed MYCBoxI. In cells, MYCN associates with thousands of intronic transcripts together with the ZCCHC8 ...[more]

PMID: 38703770

Similar Datasets

Project description:MYCN is an oncogene amplified in approximately 20% of all neuroblastomas and 50% of high risk neuroblastoma. It is a transcription factor regulating the expression of genes involved in proliferation and apoptosis.We would like to identify genes potentially regulated by MYCN in a conditional MYCN expression system. The SHEP Tet21N system is a conditional, tetracycline-regulated MYCN expression system established in the MYCN non-amplified SHEP neuroblastoma cell line (Lutz et al., 1996). Expression of MYCN is switched off by the addition of tetracycline to the growth medium. Levels of MYCN protein and RNA in the absence of tetracycline are comparable with those present in MYCN amplified cell lines (Bell et al., 2006). By performing microarray analyses on the Tet21n cell lines in the presence and absence of MYCN we hope to identify genes whose expression had been altered by MYCN either upregulated or downregulated and may be potential MYCN targets. The altered expression of some of these genes will then be validated using quantitative RTPCR and a selection will be further investigated to determine if they are MYCN transcriptional targets and may be potential candidates for anti-MYCN therapies for neuroblastoma Specific objectives 1) To investigate genes which are altered by 2 fold or more in the presence of or absence of MYCN in Tet21N cells. Refs: Bell, E., Premkumar, R., Carr, J., Lu, X., Lovat, P.E., Kees, U.R., Lunec, J. & Tweddle, D.A. (2006). The role of MYCN in the failure of MYCN amplified neuroblastoma cell lines to G1 arrest after DNA damage. Cell Cycle, 5, 2639-47. Lutz, W., Stohr, M., Schurmann, J., Wenzel, A., Lohr, A. & Schwab, M. (1996). Conditional expression of N-myc in human neuroblastoma cells increases expression of alpha-prothymosin and ornithine decarboxylase and accelerates progression into S-phase early after mitogenic stimulation of quiescent cells. Oncogene, 13, 803-12.

Project description:In neuroblastoma, amplification of the oncogenic basic helix-loop-helix (bHLH) transcription factor (TF) MYCN is the defining prognosticator of high-risk disease, occurs in one-third of neuroblastoma, and drastically reduces overall survival rates. As a proto-oncogene, targeted MYCN overexpression in peripheral neural crest is sufficient to initiate disease in mouse models. In MYCN amplified neuroblastoma, elevated expression of the factor is crucial to maintain tumor stemness and is associated with increased proliferation and aberrant cell cycle progression, as these tumors lack the ability to arrest in G1 in response to irradiation. MYCN down-regulation broadly reverses these oncogenic phenotypes in a variety of neuroblastoma models and recent thereapeutic strategies to indirectly target MYCN production or protein stability have reduced tumor growth in vivo. These observations motivate an investigation of MYCN binding in MYCN amplified tumors as it remains fundamentally unclear how elevated levels of the factor occupy the genome and alter transcriptional programs in neuroblastoma. Here we present the first dynamic chromatin and transcriptional landscape of direct MYCN perturbation in neuroblastoma. We find that at oncogenic levels, MYCN associates with E-box (CANNTG) binding motifs in an affinity dependent manner across most active cis-regulatory promoters and enhancers. MYCN shutdown globally reduces histone acetylation and transcription, consistent with prior descriptions of MYC proteins as non-linear amplifiers of gene expression. We establish that MYCN load at the promoter and proximal enhancers predicts transcriptional responsiveness to MYCN shutdown and that MYCN enhancer binding occurs prominently at the most strongly occupied and down-regulated genes, suggesting a role for these tissue specific elements in predicating MYCN responsive âtargetâ genes. At these invaded enhancers, we identify the lineage specific bHLH TWIST1 as a key collaborator and dependency of oncogenic MYCN. These data suggest that MYCN enhancer invasion helps shape transcriptional amplification of the neuroblastoma gene expression program to promote tumorigenesis. ChIP-Seq in SHEP21, BE2C, KELLY, and NGP neuroblastoma cell lines for H3K27ac, H3K4me3, RNA PolII, MYCN, BRD4, or TWIST1