Identification of a novel Drosophila SMAD on the X chromosome

Biochem Biophys Res Commun. 1998 Nov 9;252(1):195-201. doi: 10.1006/bbrc.1998.9562.


TGF-beta signaling from the cell surface to the nucleus is mediated by the SMAD family of proteins, which have been grouped into three classes based upon sequence identity and function. Receptor-regulated, or pathway-restricted, SMADs (R-SMADs) are phosphorylated by ligand-specific serine/threonine kinase receptors. Phosphorylated R-SMADs oligomerize with the coactivating, or shared, SMAD (Co-SMAD) mediator and translocate to the nucleus where the complex directs transcription of downstream target genes. Inhibitory SMADs (I-SMADs) block receptor-mediated phosphorylation of R-SMADs. In Drosophila, one member of each class of SMAD has been reported: MAD, an R-SMAD, MEDEA, a Co-SMAD, and DAD, an I-SMAD. Here, we report the first identification of a novel Drosophila R-SMAD, which we have named Smox for Smad on X. We have localized the Smox gene to a specific interval on the X chromosome and shown that Smox is transcribed throughout development.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Body Patterning
  • Chromosome Mapping
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics*
  • Drosophila Proteins*
  • Drosophila melanogaster / embryology
  • Drosophila melanogaster / genetics*
  • Embryo, Nonmammalian / physiology
  • In Situ Hybridization
  • Molecular Sequence Data
  • Repressor Proteins*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Smad Proteins, Receptor-Regulated
  • Smad4 Protein
  • Trans-Activators / chemistry
  • Trans-Activators / genetics*
  • Transcription Factors
  • Transforming Growth Factor beta / physiology
  • Vertebrates
  • X Chromosome*


  • DNA-Binding Proteins
  • Drosophila Proteins
  • MAD protein, Drosophila
  • Med protein, Drosophila
  • Repressor Proteins
  • Smad Proteins, Receptor-Regulated
  • Smad4 Protein
  • Smox protein, Drosophila
  • Trans-Activators
  • Transcription Factors
  • Transforming Growth Factor beta

Associated data

  • GENBANK/AF078529