Kcnb1-Kcng4 axis regulates Scospondin secretion and Reissner fiber development

The voltage-gated potassium channel Kv2.1 plays a role in the development of the ventricular system and the subcommissural organ in zebrafish. Here, a role for Kv2.1 in the secretion of the major component of Reissner’s fiber, Scospondin, was demonstrated. The results showed that Kv2.1 acts as a negative regulator of Scospondin secretion and Reissner fiber assembly. Kv2.1 regulates formation of Scospondin microfilaments and their assembly in Reissner fiber. Cholesterol playing a key role in Scospondin secretion. After the Reissner fiber is formed, it is detached from the hindbrain floor plate, where Scospondin produced initially. The tension of the fiber depends on its attachment to the subcommissural and flexural organs. In turn fiber tension affects the morphogenesis of these organs. This process of Reissner fiber formation depends on the input provided by the Hedgehog and Wnt/β-catenin signaling pathways on the anterior roof and floor plates.