Cloning And Characterization Of CDNA Of ZmZIP4 Encoding A Zinc Transporter From Maize

Zinc is a necessary nutrient that plays important roles in numerous physiological processes in plants,serving as a cofactor for many enzymes and as the key structural motifs in transcriptional regulatory.A deficiency of Zn,decreases growth,but excess Zn has significant toxicity to biological systems through metal-based cytotoxic reactions.Therefore, the study of the Zn uptake, transportation, storage and distribution in plants has attracted many researchers'eyes.With the swift development of genetics and experiment methods in molecular biology, the study of many the cloning and expression of many genes involved in the transportation and regulation in plants has become a new hot point in the research field . This is a study about a gene of transportation of Zn cloned from maize inbred line 178 by the method of molecular. The follow is the results of analysis on characteristics of composition ,the gene expression under low–zinc and sub-cellular localization biology and preliminary expression analysis:1. A ZIP family gene, ZmZIP4, was isolated by RT-PCR from maize. There is 1161bp in length for the Open Reading Frame (ORF) of this gene, which encodes a 38.66 kDa protein with 386 amino acids. The isoelectric point of the gene is 7.5.GenBank accession: HM048832.2. The molecular biology predicts protein encoded by ZmZIP4 is a transport protein with a ZIP family domain and seven transmembrane structure domain. There is a signal peptide in C-terminus.3. ZmZIP4 shows 70% homology and 73% identify with OsZIP4 through the amino acid sequence alignment.The results suggests it is probable that ZmZIP4 is similar mechanism with OsZIP4.4. The result of RT-PCR shows ZmZIP4 is a transport protein about Zn,Cu,Mn, while a deficiency of Zn or Cu or Mn , The transcripts of ZmZIP4 significantly increased.It is the same as OsZIP4 that the transcripts of ZmZIP4 are maximum on the third day in root compare to the fifth day in leaf under low-znic condition.It is possible that the expression of ZmZIP4 between root and leaf is different .5. The fusion expression vector pEGAD-ZmZIP4 was successfully constructed. In order to observe its position, the plasmid was inserted into the onion epidermal cell by the gene gun. The result showed that the ZmZIP4 located in the membrane.