Overexpression of HMGA2-LPP fusion transcripts promotes expression of the alpha 2 type XI collagen gene

Biochem Biophys Res Commun. 2006 Feb 10;340(2):476-81. doi: 10.1016/j.bbrc.2005.12.042. Epub 2005 Dec 20.


In a subset of human lipomas, a specific t(3;12) chromosome translocation gives rise to HMGA2-LPP fusion protein, containing the amino (N)-terminal DNA binding domains of HMGA2 fused to the carboxyl (C)-terminal LIM domains of LPP. In addition to its role in adipogenesis, several observations suggest that HMGA2-LPP is linked to chondrogenesis. Here, we analyzed whether HMGA2-LPP promotes chondrogenic differentiation, a marker of which is transactivation of the alpha 2 type XI collagen gene (Col11a2). Real-time PCR analysis showed that HMGA2-LPP and COL11A2 were co-expressed. Luciferase assay demonstrated that either of HMGA2-LPP, wild-type HMGA2 or the N-terminal HMGA2 transactivated the Col11a2 promoter in HeLa cells, while the C-terminal LPP did not. RT-PCR analysis revealed that HMGA2-LPP transcripts in lipomas with the fusion were 591-fold of full-length HMGA2 transcripts in lipomas without the fusion. These results indicate that in vivo overexpression of HMGA2-LPP promotes chondrogenesis by upregulating cartilage-specific collagen gene expression through the N-terminal DNA binding domains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites / genetics
  • Chondrogenesis / genetics
  • Collagen Type XI / biosynthesis*
  • Collagen Type XI / classification
  • Collagen Type XI / genetics*
  • Cytoskeletal Proteins / biosynthesis*
  • Cytoskeletal Proteins / genetics*
  • Cytoskeletal Proteins / physiology
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Neoplastic / physiology
  • HMGA2 Protein / biosynthesis*
  • HMGA2 Protein / genetics*
  • HMGA2 Protein / physiology
  • Humans
  • LIM Domain Proteins
  • Lipoma / genetics
  • Lipoma / metabolism
  • Mutant Chimeric Proteins / genetics*
  • Mutant Chimeric Proteins / metabolism
  • Mutant Chimeric Proteins / physiology
  • Promoter Regions, Genetic
  • Protein Structure, Tertiary / genetics


  • Collagen Type XI
  • Cytoskeletal Proteins
  • DNA-Binding Proteins
  • HMGA2 Protein
  • LIM Domain Proteins
  • LPP protein, human
  • Mutant Chimeric Proteins