First published online March 9, 2006
Development 133, 701e (2006)
© The Company of Biologists Limited
Polyhomeotic: a neuronal memory aid?
Cells `remember' their identity by maintaining patterns of transcriptional
repression that are established as they differentiate. The Polycomb-group
(PcG) proteins are important players in this cellular memory system and their
role in Hox gene regulation during embryogenesis has been extensively studied.
Now, on p. 1231, Wang
and co-workers report that the PcG protein Polyhomeotic (Ph) is required to
maintain neuronal diversity during metamorphosis in the Drosophila
brain and that other PcG proteins also function in neuronal development. The
researchers used a genetic mosaic screen in adult fly brains to isolate a new
ph mutation. In normal fly brains, different neuronal subtypes have
characteristic projection patterns and gene expression profiles, but in the
absence of ph, neurons acquire aberrant - but apparently uniform -
morphologies and cellular identities. This transformation requires a pulse of
ecdysone, leading the researchers to speculate that normal steroid hormone
signalling (which drives metamorphosis) may have detrimental side effects on
neuronal identity when PcG functions are compromised.
Related articles in Development:
- Steroid hormone-dependent transformation of polyhomeotic mutant neurons in the Drosophila brain
- Jian Wang, Ching-Hsien J. Lee, Suewei Lin, and Tzumin Lee
Development 2006 133: 1231-1240.
[Abstract]
[Full Text]
