Involvement of winged eye encoding a chromatin-associated bromo-adjacent homology domain protein in disc specification

doi:10.1073/pnas.0507945102

Involvement of winged eye encoding a chromatin-associated bromo-adjacent homology domain protein in disc specification

^*Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; ^†Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland; and ^§Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan

Contributed by Walter J. Gehring, September 12, 2005

Abstract

How organ identity is determined is a fundamental question in developmental biology. In Drosophila, field-specific selector genes, such as eyeless (ey) for eyes and vestigial (vg) for wings, participate in the determination of imaginal disc-specific identity. We performed gain-of-function screening and identified a gene named winged eye (wge), which encodes a bromo-adjacent homology domain protein that localizes at specific sites on chromosomes in a bromo-adjacent homology domain-dependent manner. Overexpression of wge-induced ectopic wings with antero-posterior and dorso-ventral axes in the eye field in a region-specific Hox gene-(Antennapedia) independent manner. Overexpression of wge was sufficient for ectopic expression of vg in eye discs. A context-dependent requirement of wge was demonstrated for vg expression in wing discs and for expression of eyes absent (eya), a control gene for eye development downstream of ey, in eye discs. In contrast to vg, however, overexpression of wge inhibited EY-mediated expression of eya. Consistent with colocalization on polytene chromosomes of WGE and Posterior sex combs (PSC), a Polycomb group gene product, we demonstrated an antagonistic genetic interaction between wge and Psc. These findings suggest that wge functions in the determination of disc-specific identity, downstream of Hox genes.

Footnotes

↵ ‡ To whom correspondence may be addressed. E-mail: walter.gehring{at}unibas.ch or kurata{at}mail.pharm.tohoku.ac.jp.
Author contributions: T.K., Y.O., W.J.G., T.A., and S.K. designed research; T.K., T.S., M.T., and S.K. performed research; T.K., W.J.G., and S.K. analyzed data; and S.K. wrote the paper.
Conflict of interest statement: No conflicts declared.
Abbreviations: AED, after egg deposition; BAH, bromo-adjacent homology; GS, gene search; IR, inverted repeat; PSC, Posterior sex combs.
Data deposition: The sequence reported in this paper has been deposited in the DDBJ/EMBL/GenBank databases (accession no. AB190214).