Two distinct mechanisms for differential positioning of gene expression borders involving the Drosophila gap protein giant

Xuelin Wu, Rajesh Vakani, Stephen Small

Research output: Contribution to journalArticlepeer-review

Abstract

We have combined genetic experiments and a targeted misexpression approach to examine the role of the gap gene giant (gt) in patterning anterior regions of the Drosophila embryo. Our results suggest that gt functions in the repression of three target genes, the gap genes Kruppel (Kr) and hunchback (hb), and the pair-rule gene even-skipped (eve). The anterior border of Kr, which lies 4-5 nucleus diameters posterior to nuclei that express gt mRNA, is set by a threshold repression mechanism involving very low levels of gt protein. In contrast, gt activity is required, but not sufficient for formation of the anterior border of eve stripe 2, which lies adjacent to nuclei that express gt mRNA. We propose that gt's role in forming this border is to potentiate repressive interaction(s) mediated by other factor(s) that are also localized to anterior regions of the early embryo. Finally, gt is required for repression of zygotic hb expression in more anterior regions of the embryo. The differential responses of these target genes to gt repression are critical for the correct positioning and maintenance of segmentation stripes, and normal anterior development.

Original languageEnglish (US)
Pages (from-to)3765-3774
Number of pages10
JournalDevelopment
Volume125
Issue number19
StatePublished - 1998

Keywords

  • Drosophila melanogaster
  • Giant
  • Patterning
  • Repression
  • Segmentation

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

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