Genetic characterization and cloning of Mothers against dpp, a gene required for decapentaplegic function in Drosophila melanogaster

• Published in: Genetics (Austin) 1995-03, Vol.139 (3), p.1347-1358
• Main Authors: Sekelsky, J.J, Newfeld, S.J, Raftery, L.A, Chartoff, E.H, Gelbart, W.M
• Format: Article
• Language: English
• Subjects: alleles; Amino Acid Sequence; amino acid sequences; Animals; Base Sequence; Chromosome Mapping; Cloning, Molecular; complementary DNA; Conserved Sequence - genetics; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; Drosophila melanogaster; Drosophila melanogaster - genetics; Drosophila melanogaster - growth & development; Drosophila Proteins; embryogenesis; Enhancer Elements, Genetic; Female; genbank/u10328; Gene Expression; gene interaction; Genes; Genes, Insect; Genetics; growth factors; Insect Hormones - genetics; Insect Hormones - metabolism; Insects; Investigations; Larva - cytology; Larva - genetics; mad gene; mad protein; Male; Molecular Sequence Data; morphogenesis; Mutation; nucleotide sequences; Phenotype; Point Mutation - genetics; polypeptides; Repressor Proteins; Sequence Homology, Amino Acid; structural genes; Transcription Factors
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/139.3.1347

The decapentaplegic (dpp) gene of Drosophila melanogaster encodes a growth factor that belongs to the transforming growth factor-beta (TGF-beta) superfamily and that plays a central role in multiple cell-cell signaling events throughout development. Through genetic screens we are seeking to identify other functions that act upstream, downstream or in concert with dpp to mediate its signaling role. We report here the genetic characterization and cloning of Mothers against dpp (Mad), a gene identified in two such screens. Mad loss-of-function mutations interact with dpp alleles to enhance embryonic dorsalventral patterning defects, as well as adult appendage defects, suggesting a role for Mad in mediating some aspect of dpp function. In support of this, homozygous Mad mutant animals exhibit defects in midgut morphogenesis, imaginal disk development and embryonic dorsal-ventral patterning that are ver,v reminiscent of dpp mutant phenoqpes. We cloned the Mad region and identified the Mad transcription unit through germline transformation rescue. We sequenced a Mad cDNA and identified three Mad point mutations that alter the coding information. The predicted MAD polypeptide lacks known protein motifs, but has strong sequence similariq to three polypeptides predicted from genomic sequence from the nematode Caenorhabditis elegans. Hence, MAD is a member of a novel, highly conserved protein family.