Abstract
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.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Cells, Cultured
-
Dimerization
-
Drosophila Proteins*
-
Drosophila melanogaster / cytology
-
Drosophila melanogaster / genetics
-
Drosophila melanogaster / growth & development
-
Drosophila melanogaster / metabolism*
-
Gene Expression Regulation, Developmental*
-
Genes, Homeobox
-
Genes, Reporter
-
Genetic Complementation Test
-
Homeodomain Proteins*
-
Insect Proteins / genetics
-
Insect Proteins / physiology*
-
LIM-Homeodomain Proteins
-
Macromolecular Substances
-
Morphogenesis / genetics
-
Nuclear Proteins / genetics
-
Nuclear Proteins / physiology*
-
Phenotype
-
Protein Conformation
-
Protein Structure, Tertiary
-
Recombinant Fusion Proteins / biosynthesis
-
Recombinant Fusion Proteins / genetics
-
Transcription Factors / genetics
-
Transcription Factors / physiology*
-
Wings, Animal / growth & development
Substances
-
Chi protein, Drosophila
-
Drosophila Proteins
-
Homeodomain Proteins
-
Insect Proteins
-
LIM-Homeodomain Proteins
-
Macromolecular Substances
-
Nuclear Proteins
-
Recombinant Fusion Proteins
-
Transcription Factors
-
ap protein, Drosophila