Shuttling of galectin-3 between the nucleus and cytoplasm.
In previous studies, we documented that galectin-3 (M(r) approximately 30,000) is a pre-mRNA splicing factor. Recently, galectin-3 was identified as a component of a nuclear and cytoplasmic complex, the survival of motor neuron complex, through its interaction with Gemin4. To test the possibility that galectin-3 may shuttle between the nucleus and the cytoplasm, human fibroblasts (LG-1) were fused with mouse fibroblasts (3T3). The monoclonal antibody NCL-GAL3, which recognizes human galectin-3 but not the mouse homolog, was used to monitor the localization of human galectin-3 in heterodikaryons. Human galectin-3 localized to both nuclei of a large percentage of heterodikaryons. Addition of the antibiotic leptomycin B, which inhibits nuclear export of galectin-3, decreased the percentage of heterodikaryons showing human galectin-3 in both nuclei. In a parallel experiment, mouse 3T3 fibroblasts, which express galectin-3, were fused with fibroblasts derived from a mouse in which the galectin-3 gene was inactivated. Mouse galectin-3 localized to both nuclei of a large percentage of heterodikaryons. Again, addition of leptomycin B restricted the presence of galectin-3 to one nucleus of a heterodikaryon. The results from both heterodikaryon assays suggest that galectin-3 can exit one nucleus, travel through the cytoplasm, and enter the second nucleus, matching the definition of shuttling.
Davidson
Peter J
PJ
Cell and Molecular Biology Program, Michigan State University, East Lansing 48824 USA.
Davis
Michael J
MJ
Patterson
Ronald J
RJ
Ripoche
Marie-Anne
MA
Poirier
Françoise
F
Wang
John L
JL
D016475:3T3 Cells; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D037502:Galectin 3 / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008856:Microscopy, Fluorescence; D021381:Protein Transport
D000911:Antibodies, Monoclonal; D037502:Galectin 3