Lmbr1^tm1Dgen

将细菌的lacZ基因插入，使其由内源性基因驱动表达β-半乳糖苷酶。RT-PCR分析显示所有检测的组织中都存在基因转录；但在任何检测的组织中，β-半乳糖苷酶的表达都不可见。 (Source: The lacZ gene from a bacterial strain was inserted so that its native promoter drives lacZ enzyme expression, and RT-PCR revealed gene transcripts in all tissues, with no detectable LacZ enzyme expression in any.)