A novel positive detection system of in vivo mutations in rpsL (strA) transgenic mice

摘要: Abstract To positively detect the in vivo mutations accumulated different mouse organs, we have developed a transgenic system. This carried an Escherichia coli (E. coli) plasmid pML4 as shuttle vector that consisted of replication origin (ori), kanamycin-resistant gene (KanR) and rpsL+) (strAS) derived from E. coli. These elements were expected to be inert system; thus, neutral would on mice. The was recovered genomic DNA introduced into kanamycin-sensitive (KmS) streptomycin-resistant (SmR) cells by using electroporation. original transformed host KmR SmS, since both KanR rpsL genes exhibited dominant traits respectively. On other hand, when retrieved mutated gene, it could detected SmR. Based this principle, able transgene integrated genome. total number rescued plasmids counted plates containing Km alone, while only mutants Sm. We so far established 22 independent lines up approx. 750 copies haploid By high-copy-number which 350 or more vector, also simple proficient method for retrieving various tissues background mutant frequency 5 × 10−5. In order validate applicability positive-detection system induced mutagenicity assay, methylnitrosourea (MNU) administered mice, increase frequencies seen all tested organs including spleen, liver brain. therefore considered provide quick-and-easy risk assessment test tissue-specific mutagenicity, positive detection streptomycin.