Cell-specific changes in expression of mRNAs encoding splice variants of aplysia cell adhesion molecule accompany long-term synaptic plasticity.
Aplysia neurons express several splice variants of apCAM, a member of the Ig superfamily of cell adhesion molecules. The major transmembrane isoform is endocytosed in sensory neurons (SNs) during the early phases of long-term facilitation (LTF) of SN synapses evoked by serotonin (5-HT) or in the motor neuron L7 during the early phases of long-term depression (LTD) of SN synapses evoked by Phe-Met-Arg-Phe-amide (FMRFa). We used single cell RT-PCR to evaluate whether expression of mRNAs encoding for different apCAM isoforms in SNs and L7 is regulated during LTF produced by 5-HT, and LTD produced by FMRFa. Single SNs and L7s express mRNAs encoding for all major isoforms, but the proportion of each isoform expressed differs for the two cells. SN expresses more mRNA encoding for GPI-linked isoforms, while L7 expresses more mRNA encoding for the major transmembrane isoform. The neuromodulators produced significant changes in the proportional levels of mRNAs encoding for specific apCAM isoforms during the first 4 h after treatments without affecting overall levels of apCAM mRNA. 5-HT evoked changes that exaggerated cell-specific differences in isoform expression. FMRFa evoked changes that reduced cell-specific differences in isoform expression. The effects of the neuromodulators on apCAM mRNA expression were not detected when cells were cultured alone or when SNs were cocultured with another motor cell that failed to induce synapse formation (L11). The results suggest that rapid cell-specific regulation of splice variant expression may contribute to different forms of long-term synaptic plasticity.
Schacher
S
S
Center for Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, 722 West 168th Street, New York, New York 10032, USA. sms2@columbia.edu
Wu
F
F
Sun
Z Y
ZY
Wang
D
D
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001048:Aplysia / Q000166:cytology / Q000378:metabolism*; D015816:Cell Adhesion Molecules, Neuronal / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology; D019835:FMRFamide / Q000494:pharmacology; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
D015816:Cell Adhesion Molecules, Neuronal; D018377:Neurotransmitter Agents; D020033:Protein Isoforms; D012333:RNA, Messenger; D012701:Serotonin; D019835:FMRFamide