Syt1 transcripts are first detected in 12-15hr embryos on northern blots and are detected at all subsequent stages tested. The are enriched in adult head relative to adult body.

(DiAntonio et al., 1993)

Syt1 transcripts are first detected in embryos at stage 13 and are detected throughout the CNS and PNS. In adults, transcripts are detected in the cell bodies of the CNS in both the brain and in the thoracic ganglia.

(DiAntonio et al., 1993)

The 4.5 kb syt transcript first appears between 8 and 12 hours of embryogenesis, and is expressed throughout development.

(Littleton et al., 1993)

The 7.0 kb syt transcript is first detected at 12 to 20 hours of embryogenesis, and is expressed throughout development.

(Littleton et al., 1993)

Syt1 transcript is detected only in neuronal cells. All peripheral nervous system (PNS) neurons, and most (if not all) central nervous system (CNS) neurons express Syt1 transcript. The first Syt1 transcripts in the CNS are detected in late stage 13 embryos, in the ventral nerve cord in a few cells per segment. This expression increases and intensifies by stage 14. In stage 15 embryos, Syt1 transcript is detected in the supraoesophageal and suboesophageal ganglia, as well as in a subset of PNS neurons. At stage 17, Syt1 transcript is abundant in both the CNS and PNS.

(Littleton et al., 1993)

On Northern blots, two transcripts of 4.5 and 7.0 kb are observed in adult head extracts with a Syt1 probe. No transcript is seen in 0-4 hour embryos and in third instar larvae.

(Perin et al., 1991)

In the adult prothorax and neck, Syt1 immunoreactivity is observed in the type I boutons of motor neurons innervating the ventral cervical muscles, prothoracic sternal anterior rotator muscle 31, and prothoracic sternal adductor muscle 33, and in the type II boutons of motorneurons innervating ventral cervical muscle 27 and prothoracic sternal anterior rotator muscle 31. Type II boutons on muscle 31 that are along the cuticle lack Syt1 immunoreactivity.

(Rivlin et al., 2004)

No protein is detected in the Syt1^D27 mutant with a polyclonal antiserum against Syt1 protein.

(DiAntonio et al., 1993)

Syt1 protein is detected in the neuropil of the adult brain. It is observed in the synapse-rich regions in the lamina, the medulla, and the lobula. Staining is also observed in the neuropil in embryonic sections. In larvae, staining is observed at the neuromuscular junctions where it is tightly confined to the nerve terminals.

(DiAntonio et al., 1993)

Immunocytochemical staining of whole mount embryos shows that Syt1 protein is rapidly transported to synapses and localizes to synaptic contact sites. In stage 14 embryos, the cell bodies of central nervous system neurons are transiently labeled. At stage 15, Syt1 protein is in the dorsal portion of the ventral nerve cord and in the brain. At stage 16, the longitudinal tracts of the central nervous system, motor neurons, and parts of the peripheral nervous system are stained. At stage 17, staining localizes to the longitudinal tracts of the central nervous system and to synapses in the body wall musculature. During larval development, Syt1 protein continues to be detected in neuromuscular junctions. Synaptic terminals in both type I and type II junctions stain. In the adult, Syt1 is detected in synapses of the adult head neuropil including those in the antennal lobes and the visual lamina.

(Littleton et al., 1993)