title: Galectin-3 interacts with components of the nuclear ribonucleoprotein complex.
abstract: The multifunctional β-galactoside-binding protein galectin-3 is found in many distinct subcellular compartments including the cell nucleus. Expression and distribution of galectin-3 between the cell nucleus and the cytosol changes during cell differentiation and cancer development. Nuclear functions of galectin-3 and how they contribute to tumorigenesis are not understood.
  
  
  
  In order to identify nuclear galectin-3 interaction partners, we used affinity chromatography and co-immunoprecipitation. Spatial proximity in the nucleus was assessed by immunofluorescence and proximity ligation assay. We also investigated the function of galectin-3 on mRNA-export by fluorescence in situ hybridization and on mRNA-processing by RNA-sequencing.
  
  
  
  The heterogeneous ribonucleoprotein particle component hnRNPA2B1 was identified as a novel galectin-3 binding protein that associates with the lectin in a lactose-dependent manner in the cell nucleus. Specific individual depletion of galectin-3 does not affect the mRNA distribution between cytoplasm and nucleus. A significant alteration of this distribution was observed after combined depletion of galectin-1 and -3. However, silencing of galectin-3 was sufficient to alter the splicing patterns of several genes.
  
  
  
  Galectin-3 and hnRNPA2B1 interact as members of the early splicing machinery. Galectin-3 and -1 have redundant functions in mRNA transport and at least in part in mRNA splicing. RNA-sequencing data points to a specific function of the hnRNPA2B1/galectin-3 interaction in the processing of transcripts coding for the nuclear oncoprotein SET.
authors.affiliation: Department of Cell Biology and Cell Pathology, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35037, Marburg, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Fritsch
authors.affiliation: Institute of Molecular Oncology, Philipps-Universität Marburg, Marburg, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Mernberger
authors.affiliation: Genomics Core Facility, Philipps-Universität Marburg, Marburg, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Nist
authors.affiliation: Institute of Molecular Oncology, Philipps-Universität Marburg, Marburg, Germany.|Genomics Core Facility, Philipps-Universität Marburg, Marburg, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Stiewe
authors.affiliation: Institute for Molecular Biology and Tumor Research, Philipps-Universität Marburg, Marburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Brehm
authors.affiliation: Department of Cell Biology and Cell Pathology, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35037, Marburg, Germany. jacob@staff.uni-marburg.de.
authors.forename: Ralf
authors.initials: R
authors.lastname: Jacob
mesh_terms: D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism; D037502:Galectin 3 / Q000235:genetics* / Q000378:metabolism; D006367:HeLa Cells; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D017404:In Situ Hybridization, Fluorescence; D008856:Microscopy, Fluorescence; D011485:Protein Binding; D034622:RNA Interference; D012326:RNA Splicing; D034443:RNA Transport; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D017423:Sequence Analysis, RNA / Q000379:methods
chemical_list: D037502:Galectin 3; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D012333:RNA, Messenger; C439768:hnRNP A2
keywords: Galectin-1; Galectin-3; RNA-processing; Spliceosome; hnRNPA2B1