spitz, a Drosophila homolog of transforming growth factor-alpha, is required in the founding photoreceptor cells of the compound eye facets

Mech Dev. 1994 Oct;48(1):13-23. doi: 10.1016/0925-4773(94)90002-7.


Cell type specification and differentiation in the developing Drosophila compound eye begins in the morphogenetic furrow. In the furrow, cells are organized into evenly spaced preclusters and there is a synchronized arrest of the cells' mitotic cycle in G1. We report that recessive spitz loss-of-function mutations affect compound eye development. Spitz is homologous to the human transforming growth factor-alpha. In mosaic clones, spitz function is required in the first photoreceptor cells to differentiate for normal ommatidial development. spitz loss-of-function mutations are dominant suppressors of EgfrE gain-of-function mutations of the epidermal growth factor-receptor gene. These data suggest that the spitz product is a precluster promoting factor. spitz transcription increases abruptly in the morphogenetic furrow, the obverse of Egfr expression. We present a model for the expression of, and cellular requirement for, this growth factor homolog.

Publication types

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

MeSH terms

  • Alleles
  • Animals
  • DNA, Complementary
  • Drosophila / embryology*
  • Drosophila / genetics
  • Eye / embryology
  • Gene Deletion
  • In Situ Hybridization
  • Microscopy, Electron, Scanning
  • Photoreceptor Cells, Invertebrate / embryology*
  • Transforming Growth Factor alpha / genetics*
  • Transforming Growth Factor alpha / metabolism


  • DNA, Complementary
  • Transforming Growth Factor alpha