Project description:Nedd4 is an E3 ubiquitin ligase that has essential roles in neural crest cell development. This study aimed to detect the gene expression changes induced by removing Nedd4 in the neural crest cell line, NCU10K, to define the molecular pathways regulated by Nedd4.
Project description:Programmed mutagenesis of the immunoglobulin locus of B-lymphocytes during class switch recombination and somatic hypermutation requires RNA polymerase II (RNA polII) transcription complex dependent targeting of the DNA mutator, Activation Induced cytidine Deaminase (AID). AID deaminates cytidine residues on substrate sequences in the immunoglobulin (Ig) locus via a transcription-dependent mechanism and this activity is stimulated by the RNA polII stalling co-factor Spt5 and the eleven-subunit cellular non-coding RNA 3’-5’ exonucleolytic processing complex, RNA exosome. The mechanism by which the RNA exosome recognizes immunoglobulin locus RNA substrates to stimulate AID DNA deamination activity on its in vivo substrate sequences is an important question. Here we report that E3-ubiquitin ligase Nedd4 destabilizes AID-associated RNA polII by a ubiquitination event leading to generation of 3’-end free RNA exosome RNA substrates at the Ig locus and other AID target sequences genome-wide. Using highthrough-out RNA sequencing technology, we find that lack of Nedd4 activity in B cells leads to accumulation of RNA exosome substrates at AID target genes. Moreover, we find that Nedd4-deficient B cells are inefficient in undergoing class switch recombination. Taken together, our study links non-coding RNA processing following RNA polymerase II pausing with regulation of the mutator AID protein. Our study also identifies Nedd4 as a regulator of non-coding RNA that are generated by stalled RNA polII genome-wide. Splenic B cells from Nedd4+/+ and Nedd4-/- B cells fetal liver chimeric mice were were stimulated in culture for IgG1 CSR. Total RNA was isolated and evaluated with whole genome RNA-seq
Project description:Tumor immune microenvironment greatly influences triple-negative breast cancer (TNBC) progression. Identifying novel targets to convert “cold” tumors into “hot” tumors holds promise for improving treatment outcomes. Here, we show that high expression of NEDD4, a HECT-type E3 ubiquitin ligase, correlates with poor prognosis and reduced CD8+ T cell infiltration in TNBC patients. NEDD4 depletion in TNBC cells significantly inhibits tumor growth through enhancing CD8+ T cell-mediated cytotoxicity in immunocompetent hosts. Mechanistically, NEDD4 depletion stabilizes β-TrCP, leading to YAP ubiquitination and degradation. Downregulated YAP reprograms the immunosuppressive tumor extracellular matrix (ECM) to increase CD8+ T cell infiltration. Furthermore, a small-molecule inhibitor of NEDD4, XMU-MP-10, exhibits significant in vivo efficacy in inhibiting TNBC tumor growth by enhancing CD8+ T cell infiltration in mouse models. Collectively, our findings suggest that the genetic depletion or pharmacological inhibition of NEDD4 enhances antitumor immune responses via the β-TrCP/YAP/ECM cascades, offering a promising therapeutic strategy for TNBC treatment.
Project description:Programmed mutagenesis of the immunoglobulin locus of B-lymphocytes during class switch recombination and somatic hypermutation requires RNA polymerase II (RNA polII) transcription complex dependent targeting of the DNA mutator, Activation Induced cytidine Deaminase (AID). AID deaminates cytidine residues on substrate sequences in the immunoglobulin (Ig) locus via a transcription-dependent mechanism and this activity is stimulated by the RNA polII stalling co-factor Spt5 and the eleven-subunit cellular non-coding RNA 3’-5’ exonucleolytic processing complex, RNA exosome. The mechanism by which the RNA exosome recognizes immunoglobulin locus RNA substrates to stimulate AID DNA deamination activity on its in vivo substrate sequences is an important question. Here we report that E3-ubiquitin ligase Nedd4 destabilizes AID-associated RNA polII by a ubiquitination event leading to generation of 3’-end free RNA exosome RNA substrates at the Ig locus and other AID target sequences genome-wide. Using highthrough-out RNA sequencing technology, we find that lack of Nedd4 activity in B cells leads to accumulation of RNA exosome substrates at AID target genes. Moreover, we find that Nedd4-deficient B cells are inefficient in undergoing class switch recombination. Taken together, our study links non-coding RNA processing following RNA polymerase II pausing with regulation of the mutator AID protein. Our study also identifies Nedd4 as a regulator of non-coding RNA that are generated by stalled RNA polII genome-wide.