The scalloped gene encodes a novel, evolutionarily conserved transcription factor required for sensory organ differentiation in Drosophila.

Abstract

The scalloped {sd) gene of Drosophila melanogaster was initially characterized by mutants affecting structures on the wing of the adult fly. The sequence of a cDNA clone of the gene reveals a predicted protein sequence homologous to that of a human transcriptional enhancer factor, TEF-1 (68% identity). The homology includes a sequence motif, the TEA domain, that was shown previously to be a DNA-binding domain of TEF-1. An sd enhancer trap strain expresses the reporter gene in a subset of neuroblasts in the central nervous system and in the peripheral sense organs of the embryo. The reporter gene is later expressed in specific regions of the imaginal discs, including regions of the wing disc destined to become structures defective in viable sd mutants. Later still, expression in the adult brain is restricted to subsets of cells, some in regions involved in the processing of gustatory information. These observations indicate that the sd gene encodes a transcription factor that functions in the regulation of cell-specific gene expression during Drosophila development, particularly in the differentiation of the nervous system.

Alternative Requirements for Vestigial, Scalloped, and Dmef2 during Muscle Differentiation inDrosophila melanogaster

“…We also tested the muscle-specific expression of two different well-characterized reporter constructs that express ␤-galactosidase (␤-gal) under the control of sd enhancers. sd ETX4 animals have an enhancer-trap (␤-gal) P-element construct inserted into the 5Ј regulatory region of the sd locus and have been used extensively to obtain the pattern of sd expression in embryo and other tissues (Campbell et al, 1992;Deshpande et al, 1997;Varadarajan and VijayRaghavan, 1999;Muller et al, 2005). Similar to what we observe with FISH detection of the sd signal, in sd ETX4 embryos, significant levels of ␤-gal can be detected in some muscle cells (Figure 2A).…”

“…Sd is the only member of the Transcriptional Enhancer Factor-1 (TEF-1) family of proteins in Drosophila (Campbell et al, 1992) and together with an activating cofactor, Vg, induce formation of the wing. In fact, ectopic expression of Vg, in the cells of the developing eye that also express Sd, leads to a respecification of these cells to a wing phenotype (Halder et al, 1998;Simmonds et al, 1998).…”

“…We have focused on the muscle-specific role of two proteins Scalloped (Sd) and Vestigial (Vg) that have been shown previously to be potent activators of fate specification in several nonmuscle cell types. There is considerable functional conservation in the activities of TEF-1/Sd and Vgl/Vg as mammalian TEF-1 can functionally substitute for Sd (Deshpande et al, 1997) and Vgl-2 can partially substitute for Vg during Drosophila development (Vaudin et al, 1999).Sd is the only member of the Transcriptional Enhancer Factor-1 (TEF-1) family of proteins in Drosophila (Campbell et al, 1992) and together with an activating cofactor, Vg, induce formation of the wing. In fact, ectopic expression of Vg, in the cells of the developing eye that also express Sd, leads to a respecification of these cells to a wing phenotype (Halder et al, 1998;Simmonds et al, 1998).…”

The Drosophila wing differentiation factor Vestigial–Scalloped is required for cell proliferation and cell survival at the dorso-ventral boundary of the wing imaginal disc

“…11 The vg-GAL4 strain that drives GAL4 expression according to part of the vgBEenhancer was provided by M Hoffmann and S Morimura. The vgBE-lacZ strain that drives b-galactosidase expression according to the vgBE enhancer was described in Williams et al 8 The sd ETX4 strain is a sd-LacZ enhancer trap described in Campbell et al 13 The E2F rm729 line, which contains an enhancer trap inserted in the dE2F1 gene, is called E2F-lacZ in this study. 22 The E2F 91 mutation is described as a null allele for the gene.…”

“…[10][11][12] vg and sd are coexpressed in the wing imaginal disc and dimerization of VG and SD seems to be a prerequisite for translocation of the dimer to the nucleus, where it acts as a functional transcription factor. [12][13][14] In fact, in the heterodimer, SD contains the transcription enhancer activator (TEA) DNA binding domain, while VG provides the transcriptional activation domain. 10,12,14 It has been shown that ectopic expression of vg in other imaginal discs induces wing outgrowths, this being dependent on the presence of SD.…”