TRANSGENIC MUTANT WITH DOPAMINERGIC SYSTEM DYSFUNCTION

我们已经确定了一个插入突变，在制造过程中， 转基因小鼠在我们的实验室，表现出异常的盘旋， 行为表现为显性表型。 这种转基因插入突变体， 我们称之为chakragati老鼠， 在出生后14-16天出现盘旋行为和运动过度活跃， 在整个青春期和成年期都不会减弱。 的 插入突变的特征是常染色体和隐性的， 稳定传输。 我们假设转基因的整合 序列导致至少一种内源性基因功能的丧失 导致多巴胺能系统的不对称和不平衡， 循环表型 在突变体中，多巴胺D2受体 对侧不对称上调的首选方向 盘旋 此外，有效的D2受体激动剂，喹吡罗， 可以提高它们盘旋的速度 我们已经绘制了 在宿主基因组中侧翼的整合位点的序列， 小鼠16号染色体和同源区的转基因序列 人类3号染色体 我们建议，在这里，确定遗传 导致异常盘旋行为的病变， 不对称D2受体上调。 作为一般方法的一部分， 我们将对整合位点进行物理表征， 然后从正常基因组中分离出整合位点上的克隆 利用侧翼标记作为杂交探针， 这些克隆中的编码序列。 我们还将寻找一个候选地点 作为我们的侧翼DNA标记之一出现的方法，根据一些 最近的基因图谱数据，可能与 多巴胺D3受体位点。 鉴于已知这些DNA标记 与D2受体基因位点无关， 据报道，对D3受体基因具有类似的高亲和力， 事实上在转基因序列整合期间被破坏， 它在插入突变体中的表达谱是异常的。 我们 我相信用分子生物学的工具来研究这个问题 插入小鼠突变体将提供新的和具体的见解， 调节运动功能的黑质纹状体系统。 这很重要 作为中枢黑质纹状体通路的扰动， 多巴胺能系统被认为是几种 神经行为障碍，包括帕金森症、精神分裂症和 可能还有其他人。

We have identified an insertional mutant, during the course of making transgenic mice in our laboratory, which exhibits an abnormal circling behavior as the overt phenotype. This transgenic insertional mutant, which we call the chakragati mouse, displays excessive lateralized circling behavior and locomotor hyperactivity by postnatal days 14-16, which persists unattenuated through adolescence and adulthood. the insertional mutation is characterized as autosomal and recessive and is stably transmitted. We hypothesize that integration of the transgene sequences has caused the loss of at least one endogenous gene function resulting in asymmetry and imbalances in the dopaminergic system and the circling phenotype. In the mutants, dopamine D2 receptors are asymmetrically upregulated contralaterally to the preferred direction of circling. Moreover, the potent D2 receptor agonist, quinpirole, was found to potentiate their rate of circling. We have mapped the DNA sequences in the host genome flanking the integration site of the transgene sequences to mouse chromosome 16 and to the homologous region of human chromosome 3. We propose, here, to identify the genetic lesion(s) that resulted in the abnormal circling behavior and asymmetrical D2 receptor upregulation. As part of a general approach, we will carry out a physical characterization of the integration site, then isolate clones across the integration site from the normal genome using the flanking markers as hybridization probes and look for gene coding sequences in these clones. We will also pursue a candidate locus approach as one of our flanking DNA markers appears, in the light of some very recent genetic mapping data, potentially coincident with the dopamine D3 receptor locus. Given that these DNA markers are known to be unlinked to the D2 receptor gene locus and that quinpirole has been reported to have a similarly high affinity for the D3 receptor gene was in fact disrupted during the integration of the transgene sequences and that its expression profile in the insertional mutant is aberrant. We believe that bringing the tools of molecular biology to bear on this insertional mouse mutant will provide novel and specific insights into nigrostriatal systems mediating motor function. This will be important as perturbations in the nigrostriatal pathways of the central dopaminergic system have been implicated to be the basis of several neurobehavioral disorders including Parkinsonism, schizophrenia, and possibly others.