MOUSE SYNAPTIC VESICULAR MONAMINE TRANSPORTER--CDNA AND GENOMIC STRUCTURE

主要脑泡单胺转运体VMAT2的活性， 是理解单胺的细胞区划的关键 这可能在调节行为和神经毒性方面发挥关键作用。 由安非他明和相关的精神刺激剂诱导。在之前的财年中， 该分支的研究人员发现了编码人类VMAT2的cDNA，以及 从ES细胞系克隆小鼠VMAT2基因和基因组DNA克隆 确定VMAT2基因组结构和主要转录起点 VMAT2基因的位点。5‘侧翼序列的序列分析 揭示了一个假定的启动子区域，该区域包含几个共识 转录因子结合的序列。对这些cDNAs和 基因组克隆允许构建用于删除的靶向载体 同源重组基因敲除小鼠的几个VMAT2外显子。 纯合基因敲除小鼠出生后不久就会死亡，但杂合小鼠 对苯丙胺奖赏和运动反应的差异 强烈指向安非他明诱导的不同影响 这两个过程上的囊泡释放。它们还显示更改过的 对MPP+多巴胺能毒性的敏感性。这些老鼠基本上 加深对精神刺激剂作用机制的认识 多巴胺能神经毒素的作用。

Activities of the principal brain vesicular monamine transporter, VMAT2, are key to understanding the cellular compartmentalization of monoamines that may play a key role in modulating the actions and neurotoxicities induced by amphetamine and related psychostimulants. In previous FYs, investigators in this Branch identified cDNAs encoding human VMAT2, and cloned murine VMAT2 cDNA and genomic DNA clones from ES cell lines and to define the VMAT2 genomic structure and major transcriptional start sites for the VMAT2 gene. Sequence analysis of 5' flanking sequences revealed a putative promoter region containing several consensus sequences for transcription factor binding. Analyses of these cDNA and genomic clones has allowed construction of targeting vectors for deletion of several VMAT2 exons in homologous recombinant Aknockout mice. Homozygous knockouts die shortly after birth, but heterozygous mice display differences in responses to amphetamine reward and locomotion that point strongly toward differential impact of amphetamine-induced vesicular release on these two processes. They also display altered sensitivity to MPP+ dopaminergic toxicity. These mice substantially enhance our understanding of mechanisms of psychostimulant and dopaminergic neurotoxin action.