Ras1-mediated modulation of Drosophila homeotic function in cell and segment identity
Boube, M.; Benassayag, C.; Seroude, L.; Cribbs, D.L.
Genetics 146(2): 619-628
1997
ISSN/ISBN: 0016-6731 PMID: 9178011 Document Number: 472759
Mutations of the Drosophila homeotic proboscipedia gene (pb; the Hox-A2/B2 homologue) provoke dose-sensitive defects, These were used to search for dose-sensitive dominant modifiers of pb function. Two identified interacting genes were the proto-oncogene Ras1 and its functional antagonist Gap1, prominent intermediaries in known signal transduction pathways. Ras1+ is a positive modifier of pb activity both in normal and ectopic cell contexts, while the Ras1-antagonist Gap1 has an opposite effect. A general role for Ras1 in homeotic function is likely, since Ras1+ activity also modulates functions of the homeotic loci Sex combs reduced and Ultrabithorax. Our data suggest that the modulation occurs by a mechanism independent of transcriptional control of the homeotic loci themselves, or of the Ras1/Gap1 genes. Taken together our data support a role for Ras1-mediated cell signaling in the homeotic control of segmental differentiation.