title: Triton, a novel family of miniature inverted-repeat transposable elements (MITEs) in Trichosanthes kirilowii Maximowicz and its effect on gene regulation.
abstract: Miniature inverted-repeat transposable elements (MITEs) have a broad impact on genome structure and function. Although MITEs are found associated to genes, little is known about their effect on gene regulation. We have identified a novel MITE family, named Triton, whilst analyzing two independent trichosanthin (TCS) gene promoters (TP9 and TP12) cloned from Trichosanthes kirilowii Maximowicz. Triton1 and Triton2 are nested in TP9, and Triton3 (with 93% sequence similarity to Triton2) is in TP12. To assess the effect of MITE insertion on TCS promoters, we excised Triton1 from TP9 and inserted it into TP12. GUS activity analysis revealed that nested Triton1 is required for effective repression of promoter activity. Detailed analyses of a series of 5'-truncated promoters concerning Triton1 showed that a dark-specific repressor and some constitutive elements endow Triton1 with ability to response to light conditions. These results suggest that Triton1 MITE, which contains cis-regulatory elements, could mediate gene expression.
authors.affiliation: National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Lijiang
authors.initials: L
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Wanqiang
authors.initials: W
authors.lastname: Qian
authors.forename: Yin
authors.initials: Y
authors.lastname: Gao
authors.forename: Chengcai
authors.initials: C
authors.lastname: An
mesh_terms: D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics / Q000302:isolation & purification; D003624:Darkness; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D017343:Genes, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics; D024363:Transcription Initiation Site; D029778:Trichosanthes / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D018744:DNA, Plant