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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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POU1F1-mediated activation of hGH-N by deoxyribonuclease I hypersensitive site II of the human growth hormone locus control region. J Mol Biol 2011; 415:29-45. [PMID: 22094313 DOI: 10.1016/j.jmb.2011.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 10/21/2011] [Accepted: 11/01/2011] [Indexed: 11/23/2022]
Abstract
The human growth hormone gene (hGH-N) is regulated by a distal locus control region (LCR) composed of five deoxyribonuclease I hypersensitive sites (HSs). The region encompassing HSI and HSII contains the predominant pituitary somatotrope-specific hGH-N activation function of the LCR. This activity was attributed primarily to POU1F1 (Pit-1) elements at HSI, as linkage to HSI was sufficient for properly regulated hGH-N expression in transgenic mice, while HSII alone had no activity. However, the presence of HSII in conjunction with HSI further enhanced hGH-N transgene expression, indicating additional determinants of pituitary hGH-N activation in the HSII region, but limitations of transgenic models and previous ex vivo systems have prevented the characterization of HSII. In the present study, we employ a novel minichromosome model of the hGH-N regulatory domain and show that HSII confers robust POU1F1-dependent activation of hGH-N in this system. This effect was accompanied by POU1F1-dependent histone acetylation and methylation throughout the minichromosome LCR/hGH-N domain. A series of in vitro DNA binding experiments revealed that POU1F1 binds to multiple sites at HSII, consistent with a direct role in HSII function. Remarkably, POU1F1 binding was localized in part to the 3' untranslated region of a primate-specific LINE-1 (long interspersed nuclear element 1) retrotransposon, suggesting that its insertion during primate evolution may have conferred function to the HSII region in the context of pituitary GH gene regulation. These observations clarify the function of HSII, expanding the role of POU1F1 in hGH LCR activity, and provide insight on the molecular evolution of the LCR.
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hGH-V gene expression and promoter activity under glucose and 5-azacytidine (5azaC) effects. Gene 2010; 452:7-15. [DOI: 10.1016/j.gene.2009.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 11/27/2009] [Accepted: 11/30/2009] [Indexed: 11/19/2022]
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Zhao J, Ding J, Li Y, Ren K, Sha J, Zhu M, Gao X. HnRNP U mediates the long-range regulation of Shh expression during limb development. Hum Mol Genet 2009; 18:3090-7. [DOI: 10.1093/hmg/ddp250] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Lunyak VV, Prefontaine GG, Núñez E, Cramer T, Ju BG, Ohgi KA, Hutt K, Roy R, García-Díaz A, Zhu X, Yung Y, Montoliu L, Glass CK, Rosenfeld MG. Developmentally Regulated Activation of a SINE B2 Repeat as a Domain Boundary in Organogenesis. Science 2007; 317:248-51. [PMID: 17626886 DOI: 10.1126/science.1140871] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The temporal and spatial regulation of gene expression in mammalian development is linked to the establishment of functional chromatin domains. Here, we report that tissue-specific transcription of a retrotransposon repeat in the murine growth hormone locus is required for gene activation. This repeat serves as a boundary to block the influence of repressive chromatin modifications. The repeat element is able to generate short, overlapping Pol II-and Pol III-driven transcripts, both of which are necessary and sufficient to enable a restructuring of the regulated locus into nuclear compartments. These data suggest that transcription of interspersed repetitive sequences may represent a developmental strategy for the establishment of functionally distinct domains within the mammalian genome to control gene activation.
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Affiliation(s)
- Victoria V Lunyak
- Howard Hughes Medical Institute, School of Medicine, University of California, San Diego, 9500 Gilman Drive, Room 345, La Jolla, CA 92093-0648, USA.
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Patrone L, Henson SE, Wall R, Malone CS. A conserved sequence upstream of the B29 (Ig beta, CD79b) gene interacts with YY1. Mol Biol Rep 2004; 31:1-11. [PMID: 15040449 DOI: 10.1023/b:mole.0000013489.04734.5e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The human, murine, and rat B29 (Ig beta, CD79b) genes are highly conserved in sequence and organization and exhibit strict B cell-specific expression. In the human and rat genomes, the B29 gene is located between the skeletal muscle-specific Na-channel alpha subunit (SCN4A) gene and the pituitary-specific growth hormone (GH-N) gene. The human pituitary-specific GH-N gene is controlled by a tissue-specific locus control region (LCR) located just upstream of the B29 promoter that mediates tissue-specific enhancement, histone acetylation, and an open chromatin conformation across the B29 gene in growth hormone (GH)-expressing pituitary cells. Here we show that B29 mRNA is not detected in a GH-expressing pituitary cell line and that GH-N mRNA is not detected in B cells. This differential expression suggests that the B29 gene is insulated or otherwise protected from the regulatory influences of the closely proximal GH LCR. We searched available sequences upstream of the human, mouse, and rat B29 genes and found a highly conserved sequence that fulfills the criteria recently established for non-coding DNA elements potentially involved in gene control. This B29 conserved sequence (BCS) bound ubiquitously expressed nuclear protein complexes. DNase I protection analysis of the BCS revealed a central 'footprinted' core which was confirmed to bind the multifunctional transcription factor, YY1. However, neither the BCS nor the YY1-binding core motif exhibited silencer or enhancer activity in transient transfections or position-independent insulator activity in enhancer-blocking assays. Thus, the BCS may function as a tissue-specific LCR or position-dependent insulator specifically countering the influences of the 5' GH LCR and controlling B29 gene expression.
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Affiliation(s)
- Lisa Patrone
- Department of Microbiology, Immunology, & Molecular Genetics, University of California, Los Angeles, CA 90095, USA
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Abstract
The plethora of genomic information gathered by the sequencing of the human and mouse genomes has paved the way for a new era of genetics. While in the past we focused mainly on the small percentage of DNA that codes for proteins, we can now concentrate on the remainder, i.e. the noncoding sequences that interrupt and separate genes. This portion of the genome is made up, in most part, of repetitive DNA sequences including DNA transposons, long terminal repeat (LTR) retrotransposons, LINEs (long interspersed nuclear elements) and SINEs (short interspersed nuclear elements). Some of these elements are transcriptionally active and can transpose or retrotranspose around the genome, resulting in insertional mutagenesis that can cause disease. In these cases, insertions have occurred in the coding sequence. However, recent evidence suggests that the main effect of these elements is their ability to influence transcription of neighbouring genes. The elements themselves contain promoters that can initiate transcription of flanking genomic DNA. Furthermore, they are susceptible to epigenetic silencing, which is often stochastic and incomplete, resulting in complex patterns of transcription. This review discusses some diseases in both human and mouse that are caused by these repetitive elements.
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Affiliation(s)
- R Druker
- School of Molecular and Microbial Biosciences, University of Sydney, New South Wales, Australia
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Giraldo P, Martínez A, Regales L, Lavado A, García-Díaz A, Alonso A, Busturia A, Montoliu L. Functional dissection of the mouse tyrosinase locus control region identifies a new putative boundary activity. Nucleic Acids Res 2003; 31:6290-305. [PMID: 14576318 PMCID: PMC275449 DOI: 10.1093/nar/gkg793] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Locus control regions (LCRs) are complex high-order chromatin structures harbouring several regulatory elements, including enhancers and boundaries. We have analysed the mouse tyrosinase LCR functions, in vitro, in cell lines and, in vivo, in transgenic mice and flies. The LCR-core (2.1 kb), located at -15 kb and carrying a previously described tissue-specific DNase I hypersensitive site, operates as a transcriptional enhancer that efficiently transactivates heterologous promoters in a cell-specific orientation-independent manner. Furthermore, we have investigated the boundary activity of these sequences in transgenic animals and cells. In mice, the LCR fragment (3.7 kb) rescued a weakly expressed reference construct that displays position effects. In Drosophila, the LCR fragment and its core insulated the expression of a white minigene reporter construct from chromosomal position effects. In cells, sequences located 5' from the LCR-core displayed putative boundary activities. We have obtained genomic sequences surrounding the LCR fragment and found a LINE1 repeated element at 5'. In B16 melanoma and L929 fibroblast mouse cells, this element was found heavily methylated, supporting the existence of putative boundary elements that could prevent the spreading of condensed chromatin from the LINE1 sequences into the LCR fragment, experimentally shown to be in an open chromatin structure.
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Affiliation(s)
- Patricia Giraldo
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
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Horan M, Millar DS, Hedderich J, Lewis G, Newsway V, Mo N, Fryklund L, Procter AM, Krawczak M, Cooper DN. Human growth hormone 1 (GH1) gene expression: complex haplotype-dependent influence of polymorphic variation in the proximal promoter and locus control region. Hum Mutat 2003; 21:408-23. [PMID: 12655556 DOI: 10.1002/humu.10167] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The proximal promoter region of the human pituitary expressed growth hormone (GH1) gene is highly polymorphic, containing at least 15 single nucleotide polymorphisms (SNPs). This variation is manifest in 40 different haplotypes, the high diversity being explicable in terms of gene conversion, recurrent mutation, and selection. Functional analysis showed that 12 haplotypes were associated with a significantly reduced level of reporter gene expression whereas 10 haplotypes were associated with a significantly increased level. The former tend to be more prevalent in the general population than the latter (p<0.01), possibly as a consequence of selection. Although individual SNPs contributed to promoter strength in a highly interactive and non-additive fashion, haplotype partitioning was successful in identifying six SNPs as major determinants of GH1 gene expression. The prediction and functional testing of hitherto unobserved super-maximal and sub-minimal promoter haplotypes was then used to test the efficacy of the haplotype partitioning approach. Electrophoretic mobility shift assays demonstrated that five SNP sites exhibit allele-specific protein binding. An association was noted between adult height and the mean in vitro expression value corresponding to an individual's GH1 promoter haplotype combination (p=0.028) although only 3.3% of the variance of adult height was found to be explicable by reference to this parameter. Three additional SNPs, identified within sites I and II of the upstream locus control region (LCR), were ascribed to three distinct LCR haplotypes. A series of LCR-GH1 proximal promoter constructs were used to demonstrate that 1) the LCR enhanced proximal promoter activity by up to 2.8-fold depending upon proximal promoter haplotype, and that 2) the activity of a given proximal promoter haplotype was also differentially enhanced by different LCR haplotypes. The genetic basis of inter-individual differences in GH1 gene expression thus appears to be extremely complex.
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Affiliation(s)
- Martin Horan
- Institute of Medical Genetics, University of Wales College of Medicine, Cardiff, UK
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Kagotani K, Nabeshima H, Kohda A, Nakao M, Taguchi H, Okumura K. Visualization of transcription-dependent association of imprinted genes with the nuclear matrix. Exp Cell Res 2002; 274:189-96. [PMID: 11900479 DOI: 10.1006/excr.2002.5478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genomic imprinting is characterized by allele-specific gene expression as a biological phenomenon. To analyze the participation of the nuclear matrix in the expression of imprinted genes, we first examined the allelic expression state of genes by simultaneously visualizing their primary transcripts and the gene sequences in individual cell nuclei using fluorescence in situ hybridization (FISH). We confirmed that each imprinted gene, SNRPN and UBE3A in human lymphocytes and Igf2 and H19 in mouse embryonic fibroblasts, mainly expressed from one allele, although some nuclei showed biallelic expression. We next visualized the gene sequences on the nuclear matrix by FISH with a tyramide signal amplification technique. Interestingly, we predominantly observed one DNA signal of imprinted genes on the nuclear matrix preparation, closely correlated with their expression patterns. Using patient cells, we confirmed that both the transcription and the binding to the nuclear matrix of the SNRPN gene occurred at the paternal allele. Our results suggest that the nuclear matrix plays an important role in gene expression, including imprinted genes, and that the FISH technique used here allows us to visualize the behaviors of genes at an individual cell level.
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Affiliation(s)
- Kazuhiro Kagotani
- Faculty of Bioresources, Mie University, 1515 Kamihama, Tsu, 514-8507, Japan
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Abstract
L1 retrotransposons comprise 17% of the human genome. Although most L1s are inactive, some elements remain capable of retrotransposition. L1 elements have a long evolutionary history dating to the beginnings of eukaryotic existence. Although many aspects of their retrotransposition mechanism remain poorly understood, they likely integrate into genomic DNA by a process called target primed reverse transcription. L1s have shaped mammalian genomes through a number of mechanisms. First, they have greatly expanded the genome both by their own retrotransposition and by providing the machinery necessary for the retrotransposition of other mobile elements, such as Alus. Second, they have shuffled non-L1 sequence throughout the genome by a process termed transduction. Third, they have affected gene expression by a number of mechanisms. For instance, they occasionally insert into genes and cause disease both in humans and in mice. L1 elements have proven useful as phylogenetic markers and may find other practical applications in gene discovery following insertional mutagenesis in mice and in the delivery of therapeutic genes.
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Affiliation(s)
- E M Ostertag
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
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