FIGURE 2

FIGURE 2

Morphological examination of hair-cell synapses in zebrafish. (A) Classically, transmission electron microscopy (TEM) has been used to visualize hair-cell synapses. Shown is a micrograph of a hair-cell synapse from a zebrafish lateral-line hair cell. In this micrograph, the presynaptic ribbon is a dark spherical density. Surrounding the presynaptic ribbon are synaptic vesicles (SV). Beneath the presynaptic ribbon along the plasma membrane is the postsynaptic density (PSD). (B) The neurod:GFP transgene (green) can be used to label the afferent neurons innervating lateral line (shown in A,B), as well as afferents that innervate inner-ear hair cells. Afferent fibers can be labeled with the commercial antibody HNK-1/Zn12 (pink). (C)Neurod:GFP (green) can be co-labeled with a Synaptophysin antibody (pink) to label both afferent fibers and all efferent synapses respectively. (D) Efferent synapses, which can also be labeled with a Vamp2 antibody (pink), can be further sub-classified by a co-label such a tyrosine hydroxylase (TH, green; white overlap indicates dopaminergic synapses). (E) Pre- and post-synaptic densities can be labeled with CtBP (pink) and pan-MAGUK (green) antibodies respectively. (F) Synaptic vesicles, labeled with cysteine string protein (CSP, pink) are enriched at the basolateral membrane of hair cells near synaptic ribbons labeled with Ribeye antibody (green). Scale bar = 100 nm in (A) and 5 μm in (E) (for B–E) and (F).