插入序列(insertion sequence IS) 700— 2000 base pair (bp) GATCGTC-GACGATC CTAGCAG- -CTGCTAG R R GATCGTC -GACGATC Stem-loop 5'GATCGTC : 3'CTAGCAG
插入序列 （ insertion sequence IS ） ● GATCGTC -GACGATC l 700 2000 base pair （bp） IR IR GATCGTC -GACGATC CTAGCAG-CTGCTAG Stem-loop 5’ GATCGTC 3’ CTAGCAG
a plasmid containing a transposon Intemal genes Inverted terminal repeats Invertedterminal repeats ransposable element- Strand separation Intra-strand annealing GGGTCTG CAGA Plasmid DNA The DNA was shadowed with heavy metal and subjected to electron microscopy.The loop- stem-loop structure is obvious
a plasmid containing a transposon The DNA was shadowed with heavy metal and subjected to electron microscopy. The loopstem-loop structure is obvious
direct repeats(直接重复，同向重复) in the DNA immediately surrounding the transposon. IS 5 ACAGTTCAG CTGAACTGT 3 3 TGTCAAGTC GACTTGACA 5 R R Insertion of IS element into chromosomal DNA the transposase cuts the target Target site DNA in a staggered fashion ↓cut Chromosomal 5' TCGAT 3 DNA 3 AGCTA Cut Inserted IS element 5 TCGAT ACAGTTCAG CTGAACTGT 3 TGTCAAGTC GACTTGACA AGCTA 5 R R Gaps filled by DNA polymerase,DNA ligase New DNA Host DNA TCGAT ACAGTTCAG CTGAACTGT TCGAT 3 3 AGCTA TGTCAAGTC GACTTGACA AGCTA New DNA R R Host DNA Duplicated target site sequence
direct repeats(直接重复，同向重复） in the DNA immediately surrounding the transposon. the transposase cuts the target DNA in a staggered fashion