Lee John M, Jung Hea-Jin, Fong Loren G, Young Stephen G
a Department of Medicine; David Geffen School of Medicine; University of California; Los Angeles, CA USA.
Nucleus. 2014 Jul-Aug;5(4):287-92. doi: 10.4161/nucl.29615.
Lamins B1 and B2 have a high degree of sequence similarity and are widely expressed from the earliest stages of development. Studies of Lmnb1 and Lmnb2 knockout mice revealed that both of the B-type lamins are crucial for neuronal migration in the developing brain. These observations naturally posed the question of whether the two B-type lamins might play redundant functions in the development of the brain. To explore that issue, Lee and coworkers generated "reciprocal knock-in mice" (knock-in mice that produce lamin B1 from the Lmnb2 locus and knock-in mice that produce lamin B2 from the Lmnb1 locus). Both lines of knock-in mice manifested neurodevelopmental abnormalities similar to those in conventional knockout mice, indicating that lamins B1 and B2 have unique functions and that increased production of one B-type lamin cannot compensate for the loss of the other.
核纤层蛋白B1和B2具有高度的序列相似性，并且从发育的最早阶段就广泛表达。对Lmnb1和Lmnb2基因敲除小鼠的研究表明，两种B型核纤层蛋白对发育中的大脑中神经元的迁移至关重要。这些观察结果自然而然地引出了一个问题，即这两种B型核纤层蛋白在大脑发育中是否可能发挥冗余功能。为了探究这个问题，李及其同事培育出了“相互敲入小鼠”（从Lmnb2基因座产生核纤层蛋白B1的敲入小鼠以及从Lmnb1基因座产生核纤层蛋白B2的敲入小鼠）。这两种敲入小鼠品系都表现出与传统基因敲除小鼠相似的神经发育异常，表明核纤层蛋白B1和B2具有独特的功能，并且一种B型核纤层蛋白产量的增加无法弥补另一种的缺失。
