title: TM6, a novel nuclear matrix attachment region, enhances its flanking gene expression through influencing their chromatin structure.
abstract: Nuclear matrix attachment regions (MARs) regulate the higher-order organization of chromatin and affect the expression of their flanking genes. In this study, a tobacco MAR, TM6, was isolated and demonstrated to remarkably increase the expression of four different promoters that drive gusA gene and adjacent nptII gene. In turn, this expression enhanced the transformation frequency of transgenic tobacco. Deletion analysis of topoisomerase II-binding site, AT-rich element, and MAR recognition signature (MRS) showed that MRS has the highest contribution (61.7%) to the TM6 sequence-mediated transcription activation. Micrococcal nuclease (MNase) accessibility assay showed that 35S and NOS promoter regions with TM6 are more sensitive than those without TM6. The analysis also revealed that TM6 reduces promoter DNA methylation which can affect the gusA expression. In addition, two tobacco chromatin-associated proteins, NtMBP1 and NtHMGB, isolated using a yeast one-hybrid system, specifically bound to the TM6II-1 region (761 bp to 870 bp) and to the MRS element in the TM6II-2 (934 bp to 1,021 bp) region, respectively. We thus suggested that TM6 mediated its chromatin opening and chromatin accessibility of its flanking promoters with consequent enhancement of transcription.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China.
authors.forename: Lusha
authors.initials: L
authors.lastname: Ji
authors.forename: Rui
authors.initials: R
authors.lastname: Xu
authors.forename: Longtao
authors.initials: L
authors.lastname: Lu
authors.forename: Jiedao
authors.initials: J
authors.lastname: Zhang
authors.forename: Guodong
authors.initials: G
authors.lastname: Yang
authors.forename: Jinguang
authors.initials: J
authors.lastname: Huang
authors.forename: Changai
authors.initials: C
authors.lastname: Wu
authors.forename: Chengchao
authors.initials: C
authors.lastname: Zheng
mesh_terms: D001665:Binding Sites / Q000235:genetics; D002843:Chromatin / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*; D019175:DNA Methylation; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D045170:Matrix Attachment Regions; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D004250:DNA Topoisomerases, Type II