目的采用不依赖连接反应的克隆法,利用T7核酸外切酶和硫代磷酸化修饰引物克隆Notch2长片段基因。方法将难以扩增的Notch2 c DNA的编码序列(7416 bp)人为分成3段,引物设计时对此3个片段和载体骨架的引物进行碱基硫代磷酸化修饰,用这些引...目的采用不依赖连接反应的克隆法,利用T7核酸外切酶和硫代磷酸化修饰引物克隆Notch2长片段基因。方法将难以扩增的Notch2 c DNA的编码序列(7416 bp)人为分成3段,引物设计时对此3个片段和载体骨架的引物进行碱基硫代磷酸化修饰,用这些引物扩增Notch2的3个片段和载体骨架。然后用T7核酸外切酶分别处理PCR产物,产生4个具有3'互补突出末端的片段,并将此4个末端突出的片段退火复性,完成Notch2基因克隆。结果琼脂糖凝胶电泳结果显示Notch2 3个片段和载体骨架的PCR产物大小与预期大小相符,经退火复性获得的克隆通过PCR、酶切和测序进行克隆鉴定,确定Notch2编码序列已经插入到pc DNA3.0-3*Flag载体中。结论利用T7核酸外切酶和引物的碱基磷酸化修饰进行的不依赖连接反应的克隆方法能够用于长片段基因的克隆。展开更多
High-throughput sequencing of amplicons has been widely used to precisely and efficiently identify species compositions and analyze community structures,greatly promoting biological studies involving large amounts of ...High-throughput sequencing of amplicons has been widely used to precisely and efficiently identify species compositions and analyze community structures,greatly promoting biological studies involving large amounts of complex samples,especially those involving environmental and pathogen-monitoring ones.Commercial library preparation kits for amplicon sequencing,which generally require multiple steps,including adapter ligation and indexing,are expensive and time-consuming,especially for applications at a large scale.To overcome these limitations,a“one-step PCR approach”has been previously proposed for constructions of amplicon libraries using long fusion primers.However,efficient amplifications of target genes and accurate demultiplexing of pooled sequencing data remain to be addressed.To tackle these,we present an integrative protocol for one-step PCR amplicon library construction(OSPALC).High-quality reads have been generated by this approach to reliably identify species compositions of mock bacterial communities and environmental samples.With this protocol,the amplicon library is constructed through one regular PCR with long primers,and the total cost per DNA/cDNA sample decreases to just 7%of the typical cost via the multi-step PCR approach.Empirically tested primers and optimized PCR conditions to construct OSPALC libraries for 16S rDNA V4 regions are demonstrated as a case study.Tools to design primers targeting at any genomic regions are also presented.In principle,OSPALC can be readily applied to construct amplicon libraries of any target genes using DNA or RNA samples,and will facilitate research in numerous fields.展开更多
基金supported by the National Natural Science Foundation of China(31961123002,31872228)the Fundamental Research Funds for the Central Universities of China(202041001)+1 种基金the Young Taishan Scholars Program of Shandong Province(tsqn201812024)the National Science Foundation(DEB-1927159).
文摘High-throughput sequencing of amplicons has been widely used to precisely and efficiently identify species compositions and analyze community structures,greatly promoting biological studies involving large amounts of complex samples,especially those involving environmental and pathogen-monitoring ones.Commercial library preparation kits for amplicon sequencing,which generally require multiple steps,including adapter ligation and indexing,are expensive and time-consuming,especially for applications at a large scale.To overcome these limitations,a“one-step PCR approach”has been previously proposed for constructions of amplicon libraries using long fusion primers.However,efficient amplifications of target genes and accurate demultiplexing of pooled sequencing data remain to be addressed.To tackle these,we present an integrative protocol for one-step PCR amplicon library construction(OSPALC).High-quality reads have been generated by this approach to reliably identify species compositions of mock bacterial communities and environmental samples.With this protocol,the amplicon library is constructed through one regular PCR with long primers,and the total cost per DNA/cDNA sample decreases to just 7%of the typical cost via the multi-step PCR approach.Empirically tested primers and optimized PCR conditions to construct OSPALC libraries for 16S rDNA V4 regions are demonstrated as a case study.Tools to design primers targeting at any genomic regions are also presented.In principle,OSPALC can be readily applied to construct amplicon libraries of any target genes using DNA or RNA samples,and will facilitate research in numerous fields.
