The level of DLDB/CHIP controls the activity of the LIM homeodomain protein apterous: evidence for a functional tetramer complex in vivo.

The LIM homeodomain (LIM-HD) protein Apterous (Ap) and its cofactor DLDB/CHIP control dorso- ventral (D/V) patterning and growth of Drosophila wing. To investigate the molecular mechanisms of Ap/CHIP function we altered their relative levels of expression and generated mutants in the LIM1, LIM2 and HD domains of Ap, as well ...
as in the LIM-interacting and self-association domains of CHIP. Using in vitro and in vivo assays we found that: (i) the levels of CHIP relative to Ap control D/V patterning; (ii) the LIM1 and LIM2 domains differ in their contributions to Ap function; (iii) Ap HD mutations cause weak dominant negative effects; (iv) overexpression of ChipDeltaSAD mutants mimics Ap lack-of-function, and this dominant negative phenotype is caused by titration of Ap because it can be rescued by adding extra Ap; and (v) overexpression of ChipDeltaLID mutants also causes an Ap lack-of-function phenotype, but it cannot be rescued by extra Ap. These results support the model that the Ap-CHIP active complex in vivo is a tetramer.
Mesh Terms:
Animals, Cells, Cultured, Dimerization, Drosophila Proteins, Drosophila melanogaster, Gene Expression Regulation, Developmental, Genes, Homeobox, Genes, Reporter, Genetic Complementation Test, Homeodomain Proteins, Insect Proteins, Macromolecular Substances, Morphogenesis, Nuclear Proteins, Phenotype, Protein Conformation, Protein Structure, Tertiary, Recombinant Fusion Proteins, Transcription Factors, Wing
EMBO J.
Date: Jun. 01, 2000
Download Curated Data For This Publication
13122
Switch View:
  • Interactions 1