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Transcription activator:like effector nucleases (TALENs) are powerful novel research tools that enable targeted gene disruption in a wide variety of model organisms,including Caenorhabditis elegans,rats,Drosophila,plants and zebrafish (1).After being transfected into the organisms,the translated TALEN protein specifically recognizes 2 adjacent sites in the chromosome and makes a double strand break in the spcacer between the two binding sites.Then the break is repaired by non:homologous end:joining (NHEJ) or homologous directed repair (HDR),resulting in random mutations or precise integration of desired DNA piece (2).In this study,we applied TALEN for the genetical manipulation of genes in parasitic nematode Strongyloides stercoralis (3).We designed 2 21:mers complementary to both opposite strands of the target site within the first exon of either daf:2 gene or ilp: 7 gene of S.stercoralis (4) and constructed TALEN vectors,in which the promoter and 3 regulatory element for TALEN expression were replaced by the promoter of S.stercoralis act2 gene and3 UTR sequence of era: 1 gene,respectively.Adult females collected from fecal cultures of infected dogs were co:injected with 1 pair of TALEN vectors (100 ng/μ 1 each) and a single strand oligo (200 ng/μ 1) complementary to the target sequence with an additional EcoRI site in it (5).After mating,the injected worms were cultured at 22 ℃ for 72 h.All progeny larvae were collected and subjected to genomic DNA extraction.Nest PCR was performed to amplify the firagment spanning the target site with the genomic DNA of wild:type worms as control template.After heating and cooling of equally mixed PCR product derived from both injected worms and wild:type worms,heteroduplex mobility assay (HMA) was conducted by running the PCR mixtures in TBE gel (6).We found that significantly retard movement of DNA bands in samples derived from both injected and wild:type worms when comparing to the sample derived only from wild:type worms,indicating that mutations were introduced into the target site and thus the heteroduplexes were produced during the heating and cooling process.This result showed that TALEN can be a valuable tool in S.stercoralis for further studies such as gene knock:out and knock:in.