Localization of SNAP-29 and Syntaxin 6 in the brain of Bombyx mori

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are a family of small conserved eukaryotic proteins that mediate fusion between organelles and the plasma membrane. Prior to fusion, complementary SNAREs, such as syntaxin, synaptosome-associated protein (SNAP), and synaptobrevin, assemble between membranes with the aid of accessory proteins that provide a scaffold to initiate SNARE zippering, pulling the membranes together, and mediating fusion. SNAP-29 and Syntaxin 6 from Bombyx mori were expressed in Escherichia coli and purified using affinity chromatography. We then produced antibodies against SNAP-29, and Syntaxin 6 of Bombyx mori in rabbits, which were used for immunohistochemistry. Immunohistochemistry results revealed that the expression of SNAP-29 was restricted to neurons in the pars intercerebralis (PI) and dorsolateral protocerebrum (DL) of the brain. The amount of SNAP-29 in the brain increases with hunger. Syntaxin 6 was restricted to neurons in the PI, the central complex (CX) and ventro-median protocerebrum (VP). SNAP-29 co-localized with SNAP-25 and Syntaxin 1A in the PI, and with Syntaxin 1A in the DL. Syntaxin 6 co-localized with SNAP-25 and Syntaxin 1A in the PI and with SNAP-25 in the CX. Bombyxin-immunopositive neurons of the brain occurred in SNAP-29 and Syntaxin 6-IRs. PTTH- and period-immunopositive neurons of the brain occurred in SNAP-29-IRs. Syntaxin 6 is present in EH secretory neurons of the brain.