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Ji L, Xu R, Lu L, Zhang J, Yang G, Huang J, Wu C, Zheng C. TM6, a novel nuclear matrix attachment region, enhances its flanking gene expression through influencing their chromatin structure. Mol Cells 2013; 36:127-37. [PMID: 23852133 PMCID: PMC3887953 DOI: 10.1007/s10059-013-0092-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/21/2013] [Accepted: 05/28/2013] [Indexed: 01/16/2023] Open
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.
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Affiliation(s)
- Lusha Ji
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
- Present address: College of Life Sciences, Liaocheng University, Liaocheng, Shandong 252059,
P.R. China
| | - Rui Xu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
| | - Longtao Lu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
- Present address: Weifang Traditional Chinese Medicine Hospital, Weifang, Shandong 261061,
P.R.China
| | - Jiedao Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
| | - Guodong Yang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
| | - Jinguang Huang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
| | - Changai Wu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
| | - Chengchao Zheng
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018,
P.R. China
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Moussavi Nik SH, Newman M, Lardelli M. The response of HMGA1 to changes in oxygen availability is evolutionarily conserved. Exp Cell Res 2011; 317:1503-12. [PMID: 21530505 DOI: 10.1016/j.yexcr.2011.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 04/05/2011] [Accepted: 04/10/2011] [Indexed: 10/18/2022]
Abstract
Zebrafish embryos have evolved to cope with hypoxia during development. This includes the ability to completely suspend embryo development for extended periods until normoxia is restored. However, only a limited number of studies have examined the gene regulatory responses of zebrafish embryos to hypoxia. The High Mobility Group A1 protein encoded by the mammalian gene HMGA1 is widely expressed during embryo development but not in adults. Its expression can be induced in adult neurons by hypoxia/oxidative stress and it is commonly reactivated in many types of cancer. We report the identification by phylogenetic and conserved synteny analyses of an HMGA1 orthologue in zebrafish, hmga1 (hmg-i/y) and analysis of sodium azide as a chemical agent for inducing hypoxia-like responses in zebrafish embryos including temporary suspension of development ("suspended animation"). Evidence was only found for the existence of the "a" isoform of HMGA1 in fish. The "b" and "c" isoforms were not detected. We show that zebrafish hmga1 is expressed in a manner similar to in mammals including its induction by hypoxia during hatching stage and in adult zebrafish brain. However, earlier during development, hypoxia causes a decrease in hmga1 transcript levels. By analysis of conservation of the HMGA1a isoform binding site in zebrafish psen2 gene transcripts, we predict that a zebrafish equivalent of the PS2V isoform of human PSEN2 is not formed and we support this by RT-PCR analyses. Thus, analysis of hmga1 function in zebrafish embryogenesis may be valuable for understanding its wider role in vertebrate development, cancer and cellular responses to hypoxia but not for analysis of the action of HMGA1 in PS2V formation.
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Affiliation(s)
- Seyyed Hani Moussavi Nik
- Discipline of Genetics, School of Molecular and Biomedical Sciences, The University of Adelaide, Australia.
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