Alternatively Splicing Interactomes Identify Novel Isoform-Specific Partners for NSD2

Weidi Wang; Yucan Chen; Jingjing Zhao; Liang Chen; Weichen Song; Li Li; Guan Ning Lin

doi:10.3389/fcell.2021.612019

Alternatively Splicing Interactomes Identify Novel Isoform-Specific Partners for NSD2

Front Cell Dev Biol. 2021 Feb 25:9:612019. doi: 10.3389/fcell.2021.612019. eCollection 2021.

Authors

Weidi Wang^{1

2}, Yucan Chen¹, Jingjing Zhao¹, Liang Chen¹, Weichen Song¹, Li Li¹, Guan Ning Lin^{1

2}

Affiliations

¹ Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
² Shanghai Key Laboratory of Psychotic Disorders, Shanghai, China.

Abstract

Nuclear receptor SET domain protein (NSD2) plays a fundamental role in the pathogenesis of Wolf-Hirschhorn Syndrome (WHS) and is overexpressed in multiple human myelomas, but its protein-protein interaction (PPI) patterns, particularly at the isoform/exon levels, are poorly understood. We explored the subcellular localizations of four representative NSD2 transcripts with immunofluorescence microscopy. Next, we used label-free quantification to perform immunoprecipitation mass spectrometry (IP-MS) analyses of the transcripts. Using the interaction partners for each transcript detected in the IP-MS results, we identified 890 isoform-specific PPI partners (83% are novel). These PPI networks were further divided into four categories of the exon-specific interactome. In these exon-specific PPI partners, two genes, RPL10 and HSPA8, were successfully confirmed by co-immunoprecipitation and Western blotting. RPL10 primarily interacted with Isoforms 1, 3, and 5, and HSPA8 interacted with all four isoforms, respectively. Using our extended NSD2 protein interactions, we constructed an isoform-level PPI landscape for NSD2 to serve as reference interactome data for NSD2 spliceosome-level studies. Furthermore, the RNA splicing processes supported by these isoform partners shed light on the diverse roles NSD2 plays in WHS and myeloma development. We also validated the interactions using Western blotting, RPL10, and the three NSD2 (Isoform 1, 3, and 5). Our results expand gene-level NSD2 PPI networks and provide a basis for the treatment of NSD2-related developmental diseases.

Keywords: NSD2; RPL10; alternatively splicing; isoform; protein–protein interaction.