The Drosophila Single-minded and Tango basic-helix-loop-helix-PAS protein heterodimer controls transcription and embryonic development of the CNS midline cells, while the Trachealess and Tango heterodimer controls tracheal cell and salivary duct transcription and development. Expression of both single-minded and trachealess is highly restricted to their respective cell lineages, however tango is broadly expressed. The developmental control of subcellular localization of these proteins is investigated because of their similarity to the mammalian basic-helix-loop-helix-PAS Aromatic hydrocarbon receptor whose nuclear localization is dependent on ligand binding. Confocal imaging of Single-minded and Trachealess protein localization indicate that they accumulate in cell nuclei when initially synthesized in their respective cell lineages and remain nuclear throughout embryogenesis. Ectopic expression experiments show that Single-minded and Trachealess are localized to nuclei in cells throughout the ectoderm and mesoderm, indicating that nuclear accumulation is not regulated in a cell-specific fashion and unlikely to be ligand dependent. In contrast, nuclear localization of Tango is developmentally regulated; it is localized to the cytoplasm in most cells except the CNS midline, salivary duct, and tracheal cells where it accumulates in nuclei. Genetic and ectopic expression experiments indicate that Tango nuclear localization is dependent on the presence of a basic-helix-loop-helix-PAS protein such as Single-minded or Trachealess. Conversely, Drosophila cell culture experiments show that Single-minded and Trachealess nuclear localization is dependent on Tango since they are cytoplasmic in the absence of Tango. These results suggest a model in which Single-minded and Trachealess dimerize with Tango in the cytoplasm of the CNS midline cells and trachea, respectively, and the dimeric complex accumulates in nuclei in a ligand-independent mode and regulates lineage-specific transcription. The lineage-specific action of Single-minded and Trachealess derives from transcriptional activation of their genes in their respective lineages, not from extracellular signaling.
Regulation of bHLH-PAS protein subcellular localization during Drosophila embryogenesis
M.P. Ward, J.T. Mosher, S.T. Crews; Regulation of bHLH-PAS protein subcellular localization during Drosophila embryogenesis. Development 1 May 1998; 125 (9): 1599–1608. doi: https://doi.org/10.1242/dev.125.9.1599
Download citation file:
Advertisement
Cited by
Development presents...
Our successful webinar series continues in 2021, with early-career researchers presenting their papers and a chance to virtually network with the developmental biology community afterwards. Here, Krisztina Ötvös tells us about the role link between nitrogen, auxin and root cell divisions.
Save your spot at our next session:
14 April
Time: 17:00 BST
Chaired by: François Guillemot
Join our mailing list to receive news and updates on the series.
The people behind the papers - Vincent Mouilleau, Célia Vaslin and Stéphane Nedelec
First authors, Vincent Mouilleau and Célia Vaslin, and their supervisor Stéphane Nedelec, talk about their latest work on HOX regulation, its potential clinical impact and where the story will take the Nedelec lab.
Special issue: call for papers
The Immune System in Development and Regeneration
Guest editors: Florent Ginhoux and Paul Martin
Submission deadline: 1 September 2021
Publication: Spring 2022
Upcoming grant deadlines
Grants awarded by The Company of Biologists help scientists travel, attend events and host sustainable activities. Make a note of the upcoming application deadlines and find out more about the grants on offer:
Sustainable Conferencing Grants
17 May 2021
Travelling Fellowships
31 May 2021
Scientific Meeting Grants
4 June 2021