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Asada K, Kotake Y, Asada R, Saunders D, Broyles RH, Towner RA, Fukui H, Floyd RA. LINE-1 hypomethylation in a choline-deficiency-induced liver cancer in rats: dependence on feeding period. J Biomed Biotechnol 2006; 2006:17142. [PMID: 16877811 PMCID: PMC1479888 DOI: 10.1155/jbb/2006/17142] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 11/28/2005] [Accepted: 12/04/2005] [Indexed: 12/30/2022] Open
Abstract
Chronic feeding of methyl-donor (methionine, choline, folic acid, and vitamin B12) deficient diet induces hepatocellular carcinoma formation in rats. Previous studies have shown that promoter CpG islands in various cancer-related genes are aberrantly methylated in this model. Moreover, the global genome in methyl-donor-deficient diet fed rats contains a lesser amount of 5-methylcytosine than control livers. It is speculated that more than 90% of all 5-methylcytosines lie within the CpG islands of the transposons, including the long/short interspersed nucleotide elements (LINE and SINE). It is considered that the 5-methylcytosines in LINE-1 limit the ability of retrotransposons to be activated and transcribed; therefore, the extent of hypomethylation of LINE-1 could be a surrogate marker for aberrant methylation in other tumor-related genes as well as genome instability. Additionally, LINE-1 methylation status has been shown to be a good indicator of genome-wide methylation. In this study, we determined cytosine methylation status in the LINE-1 repetitive sequences of rats fed a choline-deficient (CD) diet for various durations and compared these with rats fed a choline-sufficient (CS) diet. The methylation status of LINE-1 was assessed by the combined bisulfite restriction analysis (COBRA) method, where the amount of bisulfite-modified and RsaI-cleaved DNA was quantified using gel electrophoresis. Progressive hypomethylation was observed in LINE-1 of CD livers as a function of feeding time; that is, the amount of cytosine in total cytosine (methylated and unmethylated) increased from 11.1% (1 week) to 19.3% (56 weeks), whereas in the control CS livers, it increased from 9.2% to 12.9%. Hypomethylation in tumor tissues was slightly higher (6%) than the nontumorous surrounding tissue. The present result also indicates that age is a factor influencing the extent of cytosine methylation.
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Affiliation(s)
- Kiyoshi Asada
- Free Radical Biology and Aging Research Program,
Oklahoma Medical Research Foundation, Oklahoma City, Ok 73104, USA
- Third Department of Internal Medicine, Nara Medical
University, Kashihara, Nara 634-8521, Japan
| | - Yashige Kotake
- Free Radical Biology and Aging Research Program,
Oklahoma Medical Research Foundation, Oklahoma City, Ok 73104, USA
| | - Rumiko Asada
- Free Radical Biology and Aging Research Program,
Oklahoma Medical Research Foundation, Oklahoma City, Ok 73104, USA
| | - Deborah Saunders
- Free Radical Biology and Aging Research Program,
Oklahoma Medical Research Foundation, Oklahoma City, Ok 73104, USA
| | - Robert H. Broyles
- Free Radical Biology and Aging Research Program,
Oklahoma Medical Research Foundation, Oklahoma City, Ok 73104, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Rheal A. Towner
- Free Radical Biology and Aging Research Program,
Oklahoma Medical Research Foundation, Oklahoma City, Ok 73104, USA
| | - Hiroshi Fukui
- Third Department of Internal Medicine, Nara Medical
University, Kashihara, Nara 634-8521, Japan
| | - Robert A. Floyd
- Free Radical Biology and Aging Research Program,
Oklahoma Medical Research Foundation, Oklahoma City, Ok 73104, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Lombardi B, Smith ML. Tumorigenesis, protooncogene activation, and other gene abnormalities in methyl deficiency. J Nutr Biochem 1994. [DOI: 10.1016/0955-2863(94)90002-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pascale RM, Simile MM, Seddaiu MA, Daino L, Vinci MA, Pinna G, Bennati S, Gaspa L, Feo F. Chemoprevention of rat liver carcinogenesis by S-adenosyl-L-methionine: is DNA methylation involved? BASIC LIFE SCIENCES 1993; 61:219-37. [PMID: 8304933 DOI: 10.1007/978-1-4615-2984-2_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- R M Pascale
- Istituto di Patologia Generale dell'Università di Sassari, Italy
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Buzard G, Locker J. The transcription control region of the rat alpha-fetoprotein gene. DNA sequence and homology studies. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 1990; 1:33-48. [PMID: 1722723 DOI: 10.3109/10425179009041345] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The alpha-fetoprotein (AFP) gene, an important system for studying developmental and tissue-specific gene expression, is regulated mostly through the control of transcription. The promoter and cis-acting DNA elements which regulate the rat gene lie within a 7 kbp region upstream of the cap site. We have determined the sequence of this entire region. It contains several repetitive elements and a species-specific distribution of DNA methylation sites. We aligned our rat AFP sequence with fragmentary mouse and human AFP sequences to define blocks of highly conserved sequence, which we then analyzed for homology to known transcription regulatory sequences. Our analysis demonstrates that the regulatory region of the rat AFP gene is unusually complex.
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Affiliation(s)
- G Buzard
- Department of Pathology, School of Medicine, University of Pittsburgh, PA 15261
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Drinkwater RD, Blake TJ, Morley AA, Turner DR. Human lymphocytes aged in vivo have reduced levels of methylation in transcriptionally active and inactive DNA. Mutat Res 1989; 219:29-37. [PMID: 2911269 DOI: 10.1016/0921-8734(89)90038-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The amount of 5-methylated cytosine (5 mC) in the sequence CmCGG has been measured in DNA extracted from uncultured peripheral blood human lymphocytes obtained from 24 young (mean age 25) and 22 old (mean age 75) individuals. When compared with the young group the old group had significantly reduced levels of 5 mC in total genomic DNA, in transcriptionally active DNA, and in genomic DNA from which transcriptionally active sequences had been removed. In both the young and old groups transcriptionally active DNA contained 10% less 5 mC than the residual 'inactive' DNA. These results indicate that loss of genomic DNA methylation may be involved in aging in vivo and underscore the association of gene regulation with the distribution of methylation in DNA.
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Affiliation(s)
- R D Drinkwater
- Department of Haematology, School of Medicine, Flinders University, Adelaide, South Australia
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Schulz WA, Crawford N, Locker J. Albumin and alpha-fetoprotein gene expression and DNA methylation in rat hepatoma cell lines. Exp Cell Res 1988; 174:433-47. [PMID: 2448155 DOI: 10.1016/0014-4827(88)90313-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To define systems for the study of gene control and differentiation in vitro, we analyzed albumin and alpha-fetoprotein (AFP) gene expression and gene methylation in a series of rat hepatoma-derived cell lines and controls. These cell lines had several specific phenotypes: adult (high albumin and low AFP mRNA), fetal (high albumin, high AFP), embryonic (low albumin, high AFP), or undifferentiated (no albumin or AFP). The adult hepatocyte phenotype is marked by a novel 2.2-kb AFP gene transcript and high DNA methylation. In general, tumor cell lines had higher albumin and AFP gene methylation than hepatocytes in vivo. Levels of total DNA methylation did not determine the methylation patterns of specific genes, except for one cell line with hypermethylated and one with hypomethylated DNA. 5'-Hypomethylation of the AFP gene correlated with gene activity in all cases; the albumin gene showed a similar relationship, but with some exceptions. Only adult hepatocytes, not cell lines, have a unique 3'-region of AFP gene demethylation.
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Affiliation(s)
- W A Schulz
- Department of Pathology, School of Medicine, University of Pittsburgh, Pennsylvania 15261
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