The balance between the novel protein target of wingless and the Drosophila Rho-associated kinase pathway regulates planar cell polarity in the Drosophila wing.
Planar cell polarity (PCP) signaling is mediated by the serpentine receptor Frizzled (Fz) and transduced by Dishevelled (Dsh). Wingless (Wg) signaling utilizes Drosophila Frizzled 2 (DFz2) as a receptor and also requires Dsh for transducing signals to regulate cell proliferation and differentiation in many developmental contexts. Distinct pathways are activated downstream of Dsh in Wg- and Fz-signaling pathways. Recently, a number of genes, which have essential roles as downstream components of PCP signaling, have been identified in Drosophila. They include the small GTPase RhoA/Rho1, its downstream effector Drosophila rho-associated kinase (Drok), and a number of genes such as inturned (in) and fuzzy (fy), whose biochemical functions are unclear. RhoA and Drok provide a link from Fz/Dsh signaling to the modulation of actin cytoskeleton. Here we report the identification of the novel gene target of wingless (tow) by enhancer trap screening. tow expression is negatively regulated by Wg signaling in wing imaginal discs, and the balance between tow and the Drok pathway regulates wing-hair morphogenesis. A loss-of-function mutation in tow does not result in a distinct phenotype. Genetic interaction and gain-of-function studies provide evidence that Tow acts downstream of Fz/Dsh and plays a role in restricting the number of hairs that wing cells form.
Chung
Seyeon
S
School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
Kim
Sangjoon
S
Yoon
Jeongsook
J
Adler
Paul N
PN
Yim
Jeongbin
J
D000818:Animals; D016764:Cell Polarity / Q000502:physiology*; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D051157:Frizzled Receptors / Q000502:physiology; D005786:Gene Expression Regulation; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D009687:Nuclear Proteins / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000502:physiology; D014921:Wings, Animal / Q000166:cytology / Q000502:physiology*; D051155:Wnt1 Protein; D054460:rho-Associated Kinases
D029721:Drosophila Proteins; D051157:Frizzled Receptors; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; C523289:Tow protein, Drosophila; D051155:Wnt1 Protein; C058784:fz protein, Drosophila; C074622:wg protein, Drosophila; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases