[Integration sites and their characteristic analysis of piggyBac transposon in cattle genome]

As a useful tool for genetic engineering, piggyBac (PB) transposons have been widely used in more than one species of transgenosis or generating mutation studies. At present, the studies about PB transposons in cattle were few. In order to get the PB transposon integration sites and summarize its characteristics in bovine genome, donor plasmid of PB[CMV-EGFP] and helper-dependent plasmid of pcDNA-PBase were constructed and transferred into bovine fibroblasts by Amaxa basic nucleofector kit for primary mammalian fibroblasts. Cell clones stably transfected were obtained after screening by G-418. Genomic DNA of transgenic cells was extracted and the integration sites of PB transposon were detected by genome walking technology. Eight integration sites were obtained in bovine genome, although only 5 sites were mapped on chromosomes 1, 2, 11, and X chromosome. We found that PB transposon was inserted into the "TTAA" location and integrated into the intergenic non-regulatory sites between two genes. Analysis of the composition of the five bases, which was close to the side of the PB integration sites "TTAA", showed that PB 5' tended to be inserted into region rich in GC (62.5%). From the study, we got that transposition occurred in cattle genome by PB transposons and the integration site information acquired from the research will provide theoretical references for bovine study by PB transposon.