苋菜IRT1基因克隆、序列及表达分析

通过对镉超积累苋菜品种天星米铁转运蛋白基因( IRT1)的克隆、序列及表达分析,旨在为植物修复镉污染土壤奠定基础.依据同源克隆原理,通过RACE技术克隆苋菜IRT1基因及生物信息学方法分析基因序列结构和功能,Northern杂交研究基因表达.苋菜IRT1基因cDNA全长1135 bp,包含完整的阅读框,编码322个氨基酸.苋菜IRT1蛋白与已知铁转运蛋白相似性在53.70％-63.04％,具有铁转运蛋白典型的功能结构特征,即N端含有1个信号肽、氨基酸序列上具有完整的ZIP家族功能结构域( Pfam:Zip)和7个跨膜结构域(TMs).苋菜IRT1蛋白还具有1个COG0428超级家族(转运二价金属离子功能)、2个蛋白激酶C磷酸化位点和2个酪蛋白Ⅱ磷酸化位点.低铁胁迫时苋菜根中IRT1基因表达量增加,加镉处理没有改变IRT1基因表达量.因此,推断苋菜IRT1基因是ZIP家族的一员,具有转运二价金属离子功能,将基因在GenBank中注册,序列号为:GU363501,命名为AmIRT1.

Cloning, Sequence and Expression Analysis of the IRT1 Gene in Amaranthus mangostanus L.

To contribute to the development of the phytoremediation removing Cd from the soil,IRT1 gene was cloned according to homologous gene conserved region by RACE method from Amaranthus mangostanus L.,a typical Cd hyperaccumulator named Tianxingmi.Its sequence and expression character were examined by bioinformatics and northern blot analysis,respectively.Its full-length cDNA is 1135 bp and encodes a polypeptide of 322 amino acids with an entire ORF.The AmIRT1 protein showed homology to other IRT-like proteins between 53.70% and 63.04% identity.All conserved features of IRT-like proteins described previously were present in the amino acids sequence of AmIRT1 protein,such as a putative N-terminal signal peptide,a Pfam: Zip function domain and seven transmembrane domains(TMs).The AmIRT1 protein also contains COGO428 superfamily known as a divalent heavy-metal cations transporter,two protein kinase C phosphorylation sites and two casein kinase II phosphorylation site.Expression of the AmIRT1 gene was increased in roots under iron deficiency,but no significant changes in its mRNA accumulation were observed under different Cd treatments.Therefore,the present results suggested that the IRT1 protein from Amaranthus mangostanu.might be a novel member of the ZIP family with the functions as a divalent heavy-metal cations transporter.This gene named AmIRT1 had been submitted to GenBank with the accession number GU363501.