Molecular Brain Research 104 (2002) 127–131 www.elsevier.com / locate / bres Research report The 39 untranslated region of the new rat synaptic vesicle protein 2B mRNA transcript inhibits translational efficiency * Klaus Heese , Yasuo Nagai, Tohru Sawada BF Research Institute, Inc., c / o National Cardiovascular Center,5-7-1 Fujishiro-dai, Suita, Osaka 565-0873, Japan Accepted 23 May 2002 Abstract Post-transcriptional regulatory mechanisms have been shown to play a major role in gene expression in eukaryotic cells. Sequences within the 39-untranslated region (39UTR) of mRNAs have been described as being important for enhancing or inhibiting message translation. Using fluorescence microscopy, Western blotting and the reverse transcription-polymerase chain reaction (RT-PCR) method, we demonstrate that the 39UTR of the new rat transcript of synaptic vesicle protein 2B (SV2Bb) mRNA is involved in post-transcriptional regulation of SV2Bb translation. When fused to a reporter gene, this 39UTR markedly inhibited protein synthesis in transiently transfected cells and this decreased translational efficiency did not occur through changes in mRNA stability. In conclusion, our study gives new insights into unraveling the molecular mechanisms involved in the post-transcriptional regulation of the SV2B gene.  2002 Elsevier Science B.V. All rights reserved. Theme: Cellular and molecular biology Topic: Gene structure and function: general Keywords: Alzheimer’s disease; Inflammation; Neurodegeneration; Neurotoxicity; Neurotransmitter; Synapse; Transcription 1. Introduction synaptotagmins which act as important modulators of synaptic vesicle exocytosis [2,3,10]. The release of neurotransmitters from synaptic vesicles Recently, we have described a new mRNA transcript in presynaptic neurons represents one of the pivotal events variant of SV2B (SV2Bb) [7], which showed very signifi- in synaptic transmission [18]. Synaptic vesicles are the key cant up-regulation in neurons upon stimulation with Ab organelles in neurotransmitter release from nerve cells. (1-42). Both SV2B and SV2Bb mRNAs encode the One of the proteins identified is SV2, a family of three identical protein, differing only in their 39-untranslated isoforms (SV2A, B and C), which is a component of all region (39UTR). We could demonstrate that the new synaptic vesicles in vertebrates [2]. 39UTR sequence of SV2Bb is AU rich and contains SV2s are probably required for maintaining the normal several AUUUA elements which may confer post-tran- functioning of the vertebrate brain, due to their important scriptional control of expression by acting as translation 21 role as vesicular Ca -transporters and their pivotal regula- inhibitory cis-elements. 21 tory role in Ca -dependent neurotransmitter release in Post-transcriptional regulation is not limited to changes presynaptic terminals revealed by electrophysiological in message stability. Sequences within the 39UTR of studies of neurons lacking SV2s. Thus, the SV2s have a mRNAs have also been shown to be important for enhanc- key regulatory role similar for example to synapsin or ing message translation as well as for translational silenc- ing [4,12,14]. In the present study we have undertaken an analysis *Corresponding author. Tel.: 181-6-6834-7646; fax: 181-6-6872- characterizing the putative translation-inhibiting activity of 8761. E-mail address: heesek@silver.ocn.ne.jp (K. Heese). the 39UTR of SV2Bb. We have therefore studied the 0169-328X / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0169-328X(02)00326-1