Which signaling molecules are collectively responsible for dorsal–ventral forebrain patterning and midline formation?

Which signaling molecules are collectively responsible for dorsal–ventral forebrain patterning and midline formation?

• A. SHH, BMP, and WNT
• B. FGF, Notch, and JAK/STAT
• C. RA, FGF, and EGF
• D. BMP, TGF-beta, and Notch

Answer: (A)

Dorsal–ventral patterning of the forebrain and midline formation rely on signaling gradients that specify distinct regional identities along the DV axis. Sonic hedgehog acts as a ventralizing cue, produced by the ventral neural tube and midline structures, and it drives ventral forebrain fates. On the opposite side, BMPs and WNTs arise from dorsal sources like the roof plate and push tissue toward dorsal identities. The interplay of these signals shapes both the dorsal and ventral territories and helps establish midline structures by coordinating how cells respond to cues from the top and bottom of the neural tube. When these three signaling families act together, they provide the broad, coordinated patterning necessary for proper forebrain organization. The other choices lack this complementary set of signals. They emphasize pathways tied to proliferation, maintenance, or rostrocaudal aspects rather than the key dorsal–ventral patterning actors plus ventral and dorsal cues that together pattern the forebrain and define the midline.

Dorsal–ventral patterning of the forebrain and midline formation rely on signaling gradients that specify distinct regional identities along the DV axis. Sonic hedgehog acts as a ventralizing cue, produced by the ventral neural tube and midline structures, and it drives ventral forebrain fates. On the opposite side, BMPs and WNTs arise from dorsal sources like the roof plate and push tissue toward dorsal identities. The interplay of these signals shapes both the dorsal and ventral territories and helps establish midline structures by coordinating how cells respond to cues from the top and bottom of the neural tube. When these three signaling families act together, they provide the broad, coordinated patterning necessary for proper forebrain organization.

The other choices lack this complementary set of signals. They emphasize pathways tied to proliferation, maintenance, or rostrocaudal aspects rather than the key dorsal–ventral patterning actors plus ventral and dorsal cues that together pattern the forebrain and define the midline.