NGF enhances depolarization effects on SNAP-25 expression: induction of SNAP-25b isoform.
The 25 kDa synaptosomal associated protein (SNAP-25), which is implicated in neuronal plasticity and neurosecretion, exists as two isoforms generated by alternative splicing of exons 5a and 5b. The aim of the present study was to characterize factors influencing isoform expression. We report that chronic depolarization of PC12 cells alone or in the presence of NGF induces the expression of isoform-b, in addition to a 1.8- to 3-fold increase in SNAP-25 mRNA and protein as determined by immunoblotting and combined RT-PCR and Southern blot analysis. When cerebellar granule neurons were cultured in elevated K+, the predominant isoform switched from SNAP-25a to SNAP-25b. Taken together these results suggested that chronic depolarization regulates the transcription and processing of SNAP-25 mRNA.
Hepp
R
R
INSERM Unité 338, Biologie de la Communication Cellulaire and CNRS FRE 2180, Strasbourg, France.
Dupont
J L
JL
Aunis
D
D
Langley
K
K
Grant
N J
NJ
D000595:Amino Acid Sequence; D000818:Animals; D015870:Gene Expression / Q000187:drug effects; D007536:Isomerism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D020932:Nerve Growth Factor / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D016716:PC12 Cells; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013569:Synapses / Q000737:chemistry / Q000502:physiology; D050825:Synaptosomal-Associated Protein 25; D014158:Transcription, Genetic / Q000187:drug effects
D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C494210:Snap25 protein, rat; D050825:Synaptosomal-Associated Protein 25; D020932:Nerve Growth Factor