Carrier of Wingless (Cow), a Secreted Heparan Sulfate Proteoglycan, Promotes Extracellular Transport of Wingless

Abstract

Morphogens are signaling molecules that regulate growth and patterning during development by forming a gradient and activating different target genes at different concentrations. The extracellular distribution of morphogens is tightly regulated, with the Drosophila morphogen Wingless (Wg) relying on Dally-like (Dlp) and transcytosis for its distribution. However, in the absence of Dlp or endocytic activity, Wg can still move across cells along the apical (Ap) surface. We identified a novel secreted heparan sulfate proteoglycan (HSPG) that binds to Wg and promotes its extracellular distribution by increasing Wg mobility, which was thus named Carrier of Wg (Cow). Cow promotes the Ap transport of Wg, independent of Dlp and endocytosis, and this function addresses a previous gap in the understanding of Wg movement. This is the first example of a diffusible HSPG acting as a carrier to promote the extracellular movement of a morphogen.

Carrier of Wingless (Cow) Regulation ofDrosophilaNeuromuscular Junction Development

“…The Drosophila genome encodes only five HSPGs, with the following three known to affect NMJ development: transmembrane syndecan (Johnson et al, 2006); GPI-anchored Dally-like protein (Dlp;Johnson et al, 2006;; and secreted perlecan (Kamimura et al, 2013). A second secreted HSPG recently characterized in Drosophila was named Carrier of Wingless (Cow; Chang and Sun, 2014). In the developing wing disk, Cow directly binds secreted Wg and promotes its extracellular transport in an HS-dependent manner.…”

Scaling of pattern formations and morphogen gradients

“…; Gallet et al . ; Chang & Sun ). In the cytoneme model, the morphogen is transported by filopodia‐like structures called cytonemes (Ramirez‐Weber & Kornberg , ; Sato & Kornberg ; Hsiung et al .…”

“…In the transcytosis model, cells uptake morphogens via endocytosis and release them via exocytosis. By repeating these steps, morphogens gradually spread through the developmental field and form a concentration gradient (Dierick & Bejsovec 1998;Kruse et al 2004;Bollenbach et al 2007;Gallet et al 2008;Chang & Sun 2014). In the cytoneme Cells differentiate into three different types of cells according to the threshold (T1 and T2) of morphogen concentration: blue cells (high), white cells (middle), and red cells (low).…”

Cellular labeling of endogenous virus replication (CLEVR) reveals de novo insertions of the gypsy endogenous retrovirus in cell culture and in both neurons and glial cells of aging fruit flies

“…Drosophila S2 cells (R69007, Thermo Fisher Scientific) were cultured in Schneider's Drosophila Media (Thermo Fisher Scientific) supplemented with 10% Fetal Bovine Serum (Thermo Fisher Scientific) and Penicillin-Streptomycin-Glutamine (Thermo Fisher Scientific), in 75cm 2 flasks. The actin-Gal4 [72] and tubulin-Gal4 [73] plasmids were used as previous publications. Cells were transfected with 1ug of each plasmid DNA with the Effectence transfection kit (Qiagen).…”

“…After 48 hours transfection, cells were fixed in 4% Paraformaldehyde and mounted on coverslips coated in 0.5mg/ml Concanavalin A and ProLong Diamond Antifade Mountant with DAPI (Thermo Fisher Scientific). Fly adult brains and 3rd instar wing discs were dissected, fixed and immunostained as previously described [4,72]. The LacZ primary antibody was used at 1:500 dilution (A-11132, Thermo Fisher Scientific).…”