The Potassium Channel Gene BmTWK7 Contributes to Cocoon-Spinning Behavior in Bombyx mori

Potassium channels regulate membrane potential, cellular excitability, and neurotransmission, yet potential behavioral and physiological roles in the silkworm (Bombyx mori) remain unclear. Here, the roles of BmTWK7 (TWiK family of potassium channels protein 7), a gene encoding a two-pore-domain potassium (K2P) channel, were investigated using CRISPR/Cas9-mediated knockout. BmTWK7 deficiency reduced the larval heart rate and altered dorsal vessel contraction patterns, supporting a regulatory role in cardiac function. BmTWK7-deficient larvae exhibited altered cocoon-spinning behavior, including a tendency toward an expanded wandering range, altered temporal patterns of spinning rate in males, higher cocooning positions, larger spinning areas, increased cocoon floss, and a higher frequency of incomplete cocoons. BmTWK7 deficiency was further associated with reduced head GABA levels, widespread downregulation of brain GABA-related genes, and increased brain Ca2+ fluorescence. Together, these findings support the role of BmTWK7 in regulating cocoon-spinning behavior and cardiac activity, while its deficiency was associated with altered GABAergic homeostasis and increased brain Ca2+ signals, highlighting broader roles of K2P channels in insect behavior and physiology.