First published online March 5, 2008
Journal of Cell Science 121, 602e (2008)
© The Company of Biologists Limited
Clearing a Grainy picture
Similar to mammalian skin, the Drosophila cuticle maintains the surface barrier defences of the fly, protecting it from the external environment. The Grainy head (Grh) transcription factor is integral to cuticle resilience, and Grh proteins have highly conserved roles in regulating the terminal differentiation of protective epithelia. But could Grh have other functions in these epithelia? Sarah Bray and colleagues (p. 747) investigate whether Grh directly regulates the expression of components of epithelial junctions [called tight or septate junctions (SJs)]. The authors express Grh in the amnioserosa, an epidermal layer in the Drosophila embryo that lacks endogenous Grh and SJs. Dorsal closure (a process similar to wound healing) is severely disrupted in the amnioserosa cells, and this defect correlates with ectopic expression of several SJ proteins. Grh-induced expression of these proteins, together with others that contribute to adhesion complexes, probably explains the dorsal-closure-arrest phenotype by promoting enhanced adhesiveness between the dorsal epidermis and amnioserosa cells. This paper provides the first evidence in invertebrates that Grh proteins regulate the genes that encode the epithelial junctional complex.
Related articles in JCS:
- Grainy head promotes expression of septate junction proteins and influences epithelial morphogenesis
- Maithreyi Narasimha, Anne Uv, Alena Krejci, Nicholas H. Brown, and Sarah J. Bray
JCS 2008 121: 747-752.
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