Ohno Masuo, Frankland Paul W, Silva Alcino J
Department of Neurobiology, Brain Research Institute, University of California, Los Angeles 90095-1761, USA.
Curr Biol. 2002 Apr 16;12(8):654-6. doi: 10.1016/s0960-9822(02)00767-4.
We recently introduced an inducible pharmacogenetic approach where pharmacological manipulations can be used to reveal recessive mutant phenotypes in a temporally controlled manner. This approach takes advantage of synergisms between pharmacological and genetic manipulations to alter the function of specific signaling pathways. For example, mice heterozygous for a point mutation (T286A) in the alpha-calcium/calmodulin-dependent kinase II (alphaCaMKII) gene show normal learning and memory. However, a concentration of an NMDA receptor antagonist (CPP) that does not affect learning in wild-type (WT) littermates, reveals learning deficits in this heterozygote (alphaCaMKII(T286A+/-)). Here, we show that pretetanic application of a concentration of CPP (0.1 microM) ineffective in WT hippocampal slices induced deficits in alphaCaMKII(T286A+/-) slices in hippocampal long-term potentiation (LTP), a mechanism thought to be involved in learning and memory. Importantly, posttetanic application of CPP (0.1 microM) had no effect on the expression or maintenance of LTP in hippocampal slices from alphaCaMKII(T286A+/-) mice. Thus, this pharmacogenetic approach allowed us to demonstrate that NMDA receptor-dependent autophosphorylation of alphaCaMKII is required during the induction but not maintenance of LTP. This ability to temporally induce recessive mutant phenotypes could be applicable to a broad range of problems and genetic systems.
我们最近引入了一种可诱导的药物遗传学方法，通过药理学操作可以以时间可控的方式揭示隐性突变表型。该方法利用了药理学和遗传学操作之间的协同作用来改变特定信号通路的功能。例如，α-钙/钙调蛋白依赖性蛋白激酶II（αCaMKII）基因点突变（T286A）的杂合子小鼠表现出正常的学习和记忆能力。然而，一种对野生型（WT）同窝小鼠学习无影响的N-甲基-D-天冬氨酸（NMDA）受体拮抗剂（CPP）浓度，却能揭示该杂合子（αCaMKII（T286A+/-））存在学习缺陷。在此，我们表明，在WT海马切片中无效的浓度为0.1微摩尔的CPP强直刺激前应用，会在αCaMKII（T286A+/-）切片中诱导海马长时程增强（LTP）缺陷，LTP是一种被认为与学习和记忆有关的机制。重要的是，强直刺激后应用CPP（0.1微摩尔）对αCaMKII（T286A+/-）小鼠海马切片中LTP的表达或维持没有影响。因此，这种药物遗传学方法使我们能够证明，αCaMKII的NMDA受体依赖性自磷酸化在LTP的诱导过程中是必需的，但在维持过程中并非必需。这种在时间上诱导隐性突变表型的能力可能适用于广泛的问题和遗传系统。
