Interactions of the LIM-domain-binding factor Ldb1 with LIM homeodomain proteins

Nature. 1996 Nov 21;384(6606):270-2. doi: 10.1038/384270a0.


The LIM homeodomain (LIM-HD) proteins, which contain two tandem LIM domains followed by a homeodomain, are critical transcriptional regulators of embryonic development. The LIM domain is a conserved cysteine-rich zinc-binding motif found in LIM-HD and LMO (rhombotin or Ttg) proteins, cytoskeletal components, LIM kinases and other proteins. LIM domains are protein-protein interaction motifs, can inhibit binding of LIM-HD proteins to DNA and can negatively regulate LIM-HD protein function. How LIM domains exert these regulatory effects is not known. We have now isolated a new LIM-domain-binding factor, Ldb1, on the basis of its ability to interact with the LIM-HD protein Lhx1 (Lim1). High-affinity binding by Ldb1 requires paired LIM domains and is restricted to the related subgroup of LIM domains found in LIM-HD and LMO proteins. The highly conserved Xenopus Ldb protein XLdb1, interacts with Xlim-1, the Xenopus orthologue of Lhx1. When injected into Xenopus embryos, XLdb1 (or Ldb1) can synergize with Xlim-1 in the formation of partial secondary axes and in activation of the genes encoding goosecoid (gsc), chordin, NCAM and XCG7, demonstrating a functional as well as a physical interaction between the two proteins.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Homeodomain Proteins / metabolism*
  • LIM Domain Proteins
  • LIM-Homeodomain Proteins
  • Mice
  • Molecular Sequence Data
  • Protein Binding
  • Recombinant Proteins / metabolism
  • Transcription Factors
  • Xenopus
  • Xenopus Proteins*


  • DNA-Binding Proteins
  • Homeodomain Proteins
  • LIM Domain Proteins
  • LIM-Homeodomain Proteins
  • Ldb1 protein, mouse
  • Lhx1 protein, Xenopus
  • Lhx1 protein, mouse
  • Recombinant Proteins
  • Transcription Factors
  • XLdb1 protein, Xenopus
  • Xenopus Proteins

Associated data

  • GENBANK/U70375
  • GENBANK/U74360