Temporal onset of synapsin I gene expression coincides with neuronal differentiation during the development of the nervous system.
Synapsin I is the best characterized member of a family of nerve terminal-specific phosphoproteins implicated in the regulation of neurotransmitter release. During development, the expression of synapsin I correlates temporally and topographically with synapse formation, and recent physiological studies (Lu et al. [1992] Neuron 8:521-529.) have suggested that synapsin I may participate in the functional maturation of synapses. To better understand the temporal relationship between synapsin I gene expression and particular cellular events during neuronal development, we have used in situ hybridization histochemistry to localize synapsin I mRNA throughout the rat central and peripheral nervous systems during embryonic and postnatal development. From the earliest embryonic time points assayed (E12), the expression of the synapsin I gene was detectable in both the central and peripheral nervous systems. While, in general, levels of synapsin I mRNAs were high in utero, synapsin I cDNA probes revealed specific patterns of hybridization in different regions of the embryonic nervous system. To determine precisely the temporal onset of expression of the synapsin I gene during neuronal development, we examined in detail the appearance of synapsin I mRNA during the well characterized postnatal development of granule cells of the rat cerebellum and hippocampus. In both regions, the onset of synapsin I gene expression correlated with the period of stem cell commitment to terminal differentiation. Finally, our data demonstrate that, in a second phase, synapsin I gene expression increases to a maximum for a given neuronal population during a particular phase of differentiation, i.e., synaptogenesis.
Department of Neurology, University of Massachusetts Medical Center, Worcester 01655.
R H
RH
Melloni
L J
LJ
DeGennaro
D000818:Animals; D001921:Brain / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D002531:Cerebellum / Q000254:growth & development / Q000378:metabolism; D015870:Gene Expression; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism; D017403:In Situ Hybridization; D009474:Neurons / Q000166:cytology*; D017933:Peripheral Nervous System / Q000196:embryology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D016704:Synapsins / Q000235:genetics*; D013997:Time Factors
D012333:RNA, Messenger; D016704:Synapsins