文章基本信息

标题：Insertion of a knockout-first cassette in Ampd1 gene leads to neonatal death by disruption of neighboring genes expression
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作者：Yongcheng Pan ; Lusi Zhang ; Qiong Liu 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2016
卷号：6
期号：1
DOI：10.1038/srep35970
语种：English
出版社：Springer Nature
摘要：AMPD1 is an adenosine monophosphate deaminase that catalyzes the deamination of AMP to IMP. To understand the physiological function of AMPD1, we obtained a strain of Ampd1 mutant mice from KOMP repository, which was generated by a knockout-first strategy. An elevated AMP level and almost complete lack of IMP was detected in the skeletal muscle of E18.5 Ampd1(tm1a/tm1a) mice. However, Ampd1(tm1a/tm1a) mice died in 2 days postnatally, which was contradicting to previous reports. After removal of the knockout-first cassette and critical exon, mice homozygous for the Ampd1(tm1c/tm1c) and Ampd1(tm1d/tm1d) alleles survived to adulthood. RNA-seq analysis indicated that the expression of two neighboring genes, Man1a2 and Nras, were disrupted in the Ampd1(tm1a/tm1a) mice, but normal in the Ampd1(tm1c/tm1c) and Ampd1(tm1d/tm1d) mice. The neonatal lethality phenotype in the Ampd1(tm1a/tm1a) mice was consistent with the Man1a2-deficient mice. Our results indicated the knockout-first cassette may cause off-target effect by influence the expression of neighboring genes. This study, together with other reports, strongly suggests that removal of targeting cassette by site-specific recombinases is very important for the accurate phenotypic interpretation on mice generated by target mutations.