title: Functional analysis of 5' untranslated region of a TIR-NBS-encoding gene from triploid white poplar.
abstract: Genome-wide analyses have identified a set of TIR-NBS-encoding genes in plants. However, the molecular mechanism underlying the expression of these genes is still unknown. In this study, we presented a TIR-NBS-encoding gene, PtDrl02, that displayed a low level of tissue-specific expression in a triploid white poplar [(Populus tomentosa x P. bolleana) x P. tomentosa], and analyzed the effects of the 5' untranslated region (UTR) on gene expression. The 5' UTR sequence repressed the reporter activity of beta-glucuronidase (GUS) gene under PtDrl02 promoter by 113.5-fold with a staining ratio of 2.97% in the transgenic tobacco plants. Quantitative RT-PCR assays revealed that the 5' UTR sequence decreased the transcript level of the GUS reporter gene by 13.3-fold, implying a regulatory role of 5' UTR in transcription and/or mRNA destabilization. The comparison of GUS activity with the transcript abundance indicated that the 5' UTR sequence decreased the translation efficiency of target gene by 88.3%. Additionally, the analysis of the transgenic P-985/UTRDelta/GUS plants showed that both the exon1 sequence and the leading intron within the 5' UTR region were responsible for the regulation of gene expression. Our results suggested a negative effect of the 5' UTR of PtDrl02 gene on gene expression.
authors.affiliation: National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Huiquan
authors.initials: H
authors.lastname: Zheng
authors.forename: Shanzhi
authors.initials: S
authors.lastname: Lin
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Lei
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D002478:Cells, Cultured; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000502:physiology*; D005966:Glucuronidase / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics; D011123:Polyploidy; D032107:Populus / Q000235:genetics*; D017434:Protein Structure, Tertiary / Q000235:genetics; D012231:Rhizobium / Q000166:cytology / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000166:cytology / Q000235:genetics; D014162:Transfection
chemical_list: D020121:5' Untranslated Regions; D010940:Plant Proteins; D005966:Glucuronidase