The Drosophila fushi tarazu polypeptide is a DNA-binding transcriptional activator in yeast cells

Abstract

Many of the regulatory genes controlling the developmental pattern of segmentation during embryonic development in Drosophila melanogaster encode nuclear proteins containing either homoeobox or 'zinc-finger' domains with putative or demonstrated sequence-specific DNA-binding properties. One of these Drosophila homoeobox-containing proteins is encoded by the fushi tarazu (ftz) gene. The expression of ftz is spatially restricted during embryogenesis and the ftz polypeptide has an important role in different stages of development. To determine whether the ftz polypeptide is a sequence-specific DNA-binding activator of transcription, we expressed portions of ftz as fusions with the yeast transcription factor GAL4 in yeast cells. Chimaeric GAL4/ftz proteins, like GAL4 itself, activated the transcription of a GAL4-dependent reporter gene. With reporter constructs containing Drosophila-derived chromosomal DNA sequences as transcriptional elements, the ftz polypeptide acted as a sequence-specific DNA-binding transcriptional activator. In Drosophila, the ftz product may therefore be a positive regulator of transcription.