Genetic dissection of a neurodevelopmental pathway: Son of sevenless functions downstream of the sevenless and EGF receptor tyrosine kinases

Cell. 1991 Jan 11;64(1):39-48. doi: 10.1016/0092-8674(91)90207-f.


We have isolated a dominant mutation in a gene called Son of sevenless (Sos) that is an allele-specific suppressor of the sevenless phenotype. This suppressor function is autonomously required in R7 and is sensitive to the dosage of the Sos and bride of sevenless genes. Loss-of-function alleles of Sos are recessive lethals, but in the eye Sos has a role in R cell development. Mutations in Sos also interact with the Ellipse allele of the Drosophila EGF receptor. We propose a model suggesting that the Sos product is downstream of sevenless and the EGF receptor, and that the dominant suppression results from the overexpression or increased activity of the gene product.

Publication types

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

MeSH terms

  • Alleles
  • Animals
  • Chromosome Mapping
  • Drosophila / anatomy & histology
  • Drosophila / genetics*
  • ErbB Receptors / genetics*
  • Eye / anatomy & histology
  • Eye / ultrastructure
  • Genes, Recessive
  • Genes, Suppressor*
  • Genetic Complementation Test
  • Genotype
  • Models, Genetic
  • Mosaicism
  • Phenotype
  • Protein-Tyrosine Kinases / genetics*


  • ErbB Receptors
  • Protein-Tyrosine Kinases