CARB 14 |
| Galectin-1 (Gal1) and galectin-3 (Gal3) are two members of the family of â-galactoside-binding proteins found in the nucleus and cytoplasm of cells. Several key findings indicate that Gal1 and Gal3 are involved in the splicing of pre-mRNA: (a) nuclear extracts, capable of carrying out splicing in a cell-free assay, contain both Gal1 and Gal3; (b) depletion of both galectins from nuclear extract results in the concomitant loss of splicing activity; (c) either recombinant Gal1 or Gal3 is able to reconstitute splicing activity in the galectin-depleted extract; and (d) immunoprecipitation of a splicing reaction containing 32P-labeled pre-mRNA results in the coprecipitation of spliceosomal complexes, a conclusion based on finding radioactive RNA species that are produced on the spliceosome. In the absence of a pre-mRNA scaffold, Gal1/Gal3 can be assembled into a macromolecular complex that contains the five uracil-rich small nuclear RNAs required for splicing, as well as several proteins previously identified on spliceosomes. |
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Galectins: Structures, Functions and Therapeutic Targets
9:00 AM-12:10 PM, Monday, August 20, 2007 BCEC -- 162B, Oral
Division of Carbohydrate Chemistry |