RESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Long non-coding RNAs (lncRNAs) are important regulatory molecules that are implicated in cellular physiology and pathology. In this work, we dissect the functional role of the HOXB-AS3 lncRNA in patients with NPM1-mutated (NPM1mut) acute myeloid leukemia (AML). We show that HOXB-AS3 regulates the proliferative capacity of NPM1mut AML blasts in vitro and in vivo. HOXB-AS3 is shown to interact with the ErbB3-binding protein 1 (EBP1) and guide EBP1 to the ribosomal DNA locus. Via this mechanism, HOXB-AS3 regulates ribosomal RNA transcription and de novo protein synthesis. We propose that in the context of NPM1 mutations, HOXB-AS3 overexpression acts as a compensatory mechanism, which allows adequate protein production in leukemic blasts.
Assuntos
Leucemia Mieloide/genética , Mutação , Proteínas Nucleares/genética , RNA Longo não Codificante/genética , RNA Ribossômico/genética , Transcrição Gênica , Doença Aguda , Animais , Linhagem Celular Tumoral , Proliferação de Células , Células HEK293 , Humanos , Células K562 , Leucemia Mieloide/patologia , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Nucleofosmina , Biossíntese de Proteínas/genética , Células THP-1 , Transplante HeterólogoRESUMO
The exon junction complex (EJC) deposited upstream of mRNA exon junctions shapes structure, composition, and fate of spliced mRNA ribonucleoprotein particles (mRNPs). To achieve this, the EJC core nucleates assembly of a dynamic shell of peripheral proteins that function in diverse post-transcriptional processes. To illuminate consequences of EJC composition change, we purified EJCs from human cells via peripheral proteins RNPS1 and CASC3. We show that the EJC originates as an SR-rich mega-dalton-sized RNP that contains RNPS1 but lacks CASC3. Sometime before or during translation, the EJC undergoes compositional and structural remodeling into an SR-devoid monomeric complex that contains CASC3. Surprisingly, RNPS1 is important for nonsense-mediated mRNA decay (NMD) in general, whereas CASC3 is needed for NMD of only select mRNAs. The switch to CASC3-EJC slows down NMD. Overall, the EJC compositional switch dramatically alters mRNP structure and specifies two distinct phases of EJC-dependent NMD.