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Cevik SE, Skaar DA, Jima DD, Liu AJ, Østbye T, Whitson HE, Jirtle RL, Hoyo C, Planchart A. DNA methylation of imprint control regions associated with Alzheimer's disease in non-Hispanic Blacks and non-Hispanic Whites. Clin Epigenetics 2024; 16:58. [PMID: 38658973 PMCID: PMC11043040 DOI: 10.1186/s13148-024-01672-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 04/13/2024] [Indexed: 04/26/2024] Open
Abstract
Alzheimer's disease (AD) prevalence is twice as high in non-Hispanic Blacks (NHBs) as in non-Hispanic Whites (NHWs). The objective of this study was to determine whether aberrant methylation at imprint control regions (ICRs) is associated with AD. Differentially methylated regions (DMRs) were bioinformatically identified from whole-genome bisulfite sequenced DNA derived from brain tissue of 9 AD (5 NHBs and 4 NHWs) and 8 controls (4 NHBs and 4 NHWs). We identified DMRs located within 120 regions defined as candidate ICRs in the human imprintome ( https://genome.ucsc.edu/s/imprintome/hg38.AD.Brain_track ). Eighty-one ICRs were differentially methylated in NHB-AD, and 27 ICRs were differentially methylated in NHW-AD, with two regions common to both populations that are proximal to the inflammasome gene, NLRP1, and a known imprinted gene, MEST/MESTIT1. These findings indicate that early developmental alterations in DNA methylation of regions regulating genomic imprinting may contribute to AD risk and that this epigenetic risk differs between NHBs and NHWs.
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Affiliation(s)
- Sebnem E Cevik
- Toxicology Program, North Carolina State University, Raleigh, NC, USA
| | - David A Skaar
- Toxicology Program, North Carolina State University, Raleigh, NC, USA
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Dereje D Jima
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
| | - Andy J Liu
- Department of Neurology, School of Medicine, Duke University, Durham, NC, USA
| | - Truls Østbye
- Department of Family Medicine and Community Health, Duke University, Durham, NC, USA
| | - Heather E Whitson
- Department of Medicine, School of Medicine, Duke University, Durham, NC, USA
- Duke Center for the Study of Aging and Human Development, Durham, NC, USA
- Duke/UNC Alzheimer's Disease Research Center (ADRC), Durham, NC, USA
| | - Randy L Jirtle
- Toxicology Program, North Carolina State University, Raleigh, NC, USA.
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
| | - Cathrine Hoyo
- Toxicology Program, North Carolina State University, Raleigh, NC, USA.
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
| | - Antonio Planchart
- Toxicology Program, North Carolina State University, Raleigh, NC, USA
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
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Carreras-Gallo N, Dwaraka VB, Jima DD, Skaar DA, Mendez TL, Planchart A, Zhou W, Jirtle RL, Smith R, Hoyo C. Creation and Validation of the First Infinium DNA Methylation Array for the Human Imprintome. bioRxiv 2024:2024.01.15.575646. [PMID: 38293193 PMCID: PMC10827131 DOI: 10.1101/2024.01.15.575646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Background Differentially methylated imprint control regions (ICRs) regulate the monoallelic expression of imprinted genes. Their epigenetic dysregulation by environmental exposures throughout life results in the formation of common chronic diseases. Unfortunately, existing Infinium methylation arrays lack the ability to profile these regions adequately. Whole genome bisulfite sequencing (WGBS) is the unique method able to profile these regions, but it is very expensive and it requires not only a high coverage but it is also computationally intensive to assess those regions. Findings To address this deficiency, we developed a custom methylation array containing 22,819 probes. Among them, 9,757 probes map to 1,088 out of the 1,488 candidate ICRs recently described. To assess the performance of the array, we created matched samples processed with the Human Imprintome array and WGBS, which is the current standard method for assessing the methylation of the Human Imprintome. We compared the methylation levels from the shared CpG sites and obtained a mean R 2 = 0.569. We also created matched samples processed with the Human Imprintome array and the Infinium Methylation EPIC v2 array and obtained a mean R 2 = 0.796. Furthermore, replication experiments demonstrated high reliability (ICC: 0.799-0.945). Conclusions Our custom array will be useful for replicable and accurate assessment, mechanistic insight, and targeted investigation of ICRs. This tool should accelerate the discovery of ICRs associated with a wide range of diseases and exposures, and advance our understanding of genomic imprinting and its relevance in development and disease formation throughout the life course.
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Vidal AC, Chandramouli SA, Marchesoni J, Brown N, Liu Y, Murphy SK, Maguire R, Wang Y, Abdelmalek MF, Mavis AM, Bashir MR, Jima D, Skaar DA, Hoyo C, Moylan CA. AHRR Hypomethylation mediates the association between maternal smoking and metabolic profiles in children. Hepatol Commun 2023; 7:e0243. [PMID: 37755881 PMCID: PMC10531191 DOI: 10.1097/hc9.0000000000000243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 07/09/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND Tobacco smoking during pregnancy is associated with metabolic dysfunction in children, but mechanistic insights remain limited. Hypomethylation of cg05575921 in the aryl hydrocarbon receptor repressor (AHRR) gene is associated with in utero tobacco smoke exposure. In this study, we evaluated whether AHRR hypomethylation mediates the association between maternal smoking and metabolic dysfunction in children. METHODS We assessed metabolic dysfunction using liver fat content (LFC), serum, and clinical data in children aged 7-12 years (n=78) followed since birth. Maternal smoking was self-reported at 12 weeks gestation. Methylation was measured by means of pyrosequencing at 3 sequential CpG sites, including cg05575921, at birth and at ages 7-12. Regression models were used to evaluate whether AHRR methylation mediated the association between maternal smoking and child metabolic dysfunction. RESULTS Average AHRR methylation at birth was significantly higher among children of nonsmoking mothers compared with children of mothers who smoked (69.8% ± 4.4% vs. 63.5% ± 5.5, p=0.0006). AHRR hypomethylation at birth was associated with higher liver fat content (p=0.01), triglycerides (p=0.01), and alanine aminotransferase levels (p=0.03), and lower HDL cholesterol (p=0.01) in childhood. AHRR hypomethylation significantly mediated associations between maternal smoking and liver fat content (indirect effect=0.213, p=0.018), triglycerides (indirect effect=0.297, p=0.044), and HDL cholesterol (indirect effect = -0.413, p=0.007). AHRR methylation in childhood (n=78) was no longer significantly associated with prenatal smoke exposure or child metabolic parameters (p>0.05). CONCLUSIONS AHRR hypomethylation significantly mediates the association between prenatal tobacco smoke exposure and features of childhood metabolic dysfunction, despite the lack of persistent hypomethylation of AHRR into childhood. Further studies are needed to replicate these findings and to explore their causal and long-term significance.
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Affiliation(s)
- Adriana C. Vidal
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | | | - Joddy Marchesoni
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Nia Brown
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Yukun Liu
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Susan K. Murphy
- Department of Obstetrics and Gynecology, Division of Reproductive Sciences, Duke University Medical Center, Durham, North Carolina, USA
| | - Rachel Maguire
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Yaxu Wang
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Manal F. Abdelmalek
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Alisha M. Mavis
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Duke University Medical Center, Durham, North Carolina, USA
| | - Mustafa R. Bashir
- Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Dereje Jima
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
- Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina, USA
| | - David A. Skaar
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Cathrine Hoyo
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Cynthia A. Moylan
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
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Jima DD, Skaar DA, Planchart A, Motsinger-Reif A, Cevik SE, Park SS, Cowley M, Wright F, House J, Liu A, Jirtle RL, Hoyo C. Genomic map of candidate human imprint control regions: the imprintome. Epigenetics 2022; 17:1920-1943. [PMID: 35786392 PMCID: PMC9665137 DOI: 10.1080/15592294.2022.2091815] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Imprinted genes – critical for growth, metabolism, and neuronal function – are expressed from one parental allele. Parent-of-origin-dependent CpG methylation regulates this expression at imprint control regions (ICRs). Since ICRs are established before tissue specification, these methylation marks are similar across cell types. Thus, they are attractive for investigating the developmental origins of adult diseases using accessible tissues, but remain unknown. We determined genome-wide candidate ICRs in humans by performing whole-genome bisulphite sequencing (WGBS) of DNA derived from the three germ layers and from gametes. We identified 1,488 hemi-methylated candidate ICRs, including 19 of 25 previously characterized ICRs (https://humanicr.org/). Gamete methylation approached 0% or 100% in 332 ICRs (178 paternally and 154 maternally methylated), supporting parent-of-origin-specific methylation, and 65% were in well-described CTCF-binding or DNaseI hypersensitive regions. This draft of the human imprintome will allow for the systematic determination of the role of early-acquired imprinting dysregulation in the pathogenesis of human diseases and developmental and behavioural disorders.
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Affiliation(s)
- Dereje D Jima
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.,Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
| | - David A Skaar
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Toxicology Program, North Carolina State University, Raleigh, NC, USA
| | - Antonio Planchart
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Toxicology Program, North Carolina State University, Raleigh, NC, USA
| | - Alison Motsinger-Reif
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Sebnem E Cevik
- Toxicology Program, North Carolina State University, Raleigh, NC, USA
| | - Sarah S Park
- Toxicology Program, North Carolina State University, Raleigh, NC, USA.,Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Michael Cowley
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Toxicology Program, North Carolina State University, Raleigh, NC, USA
| | - Fred Wright
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.,Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
| | - John House
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Toxicology Program, North Carolina State University, Raleigh, NC, USA.,National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Andy Liu
- Department of Neurology, Duke University, School of Medicine, Durham, NC, USA
| | - Randy L Jirtle
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Toxicology Program, North Carolina State University, Raleigh, NC, USA
| | - Cathrine Hoyo
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Toxicology Program, North Carolina State University, Raleigh, NC, USA
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5
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Skaar DA, Dietze EC, Alva-Ornelas JA, Ann D, Schones DE, Hyslop T, Sistrunk C, Zalles C, Ambrose A, Kennedy K, Idassi O, Miranda Carboni G, Gould MN, Jirtle RL, Seewaldt VL. Epigenetic Dysregulation of KCNK9 Imprinting and Triple-Negative Breast Cancer. Cancers (Basel) 2021; 13:cancers13236031. [PMID: 34885139 PMCID: PMC8656495 DOI: 10.3390/cancers13236031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 11/26/2021] [Indexed: 12/02/2022] Open
Abstract
Simple Summary Genomic imprinting is an inherited form of parent-of-origin specific epigenetic gene regulation that is dysregulated by poor prenatal nutrition and environmental toxins. Here, we showed that KCNK9 is imprinted in breast tissue and identified the differentially methylated region (DMR) controlling its imprint status. Hypomethylation at the DMR, coupled with biallelic expression of KCNK9, occurred in 63% of triple-negative breast cancers (TNBC). The association between hypomethylation and TNBC status was highly significant in African-Americans (p = 0.006), but not in Caucasians (p = 0.70). The high frequency of KCNK9 DMR hypomethylation in TNBC and non-cancerous breast tissue from high-risk women provides evidence that hypomethylation of the KNCK9 DMR/TASK3 overexpression may provide a new target for prevention of TNBC. Abstract Genomic imprinting is an inherited form of parent-of-origin specific epigenetic gene regulation that is dysregulated by poor prenatal nutrition and environmental toxins. KCNK9 encodes for TASK3, a pH-regulated potassium channel membrane protein that is overexpressed in 40% of breast cancer. However, KCNK9 gene amplification accounts for increased expression in <10% of these breast cancers. Here, we showed that KCNK9 is imprinted in breast tissue and identified a differentially methylated region (DMR) controlling its imprint status. Hypomethylation at the DMR, coupled with biallelic expression of KCNK9, occurred in 63% of triple-negative breast cancers (TNBC). The association between hypomethylation and TNBC status was highly significant in African-Americans (p = 0.006), but not in Caucasians (p = 0.70). KCNK9 hypomethylation was also found in non-cancerous tissue from 77% of women at high-risk of developing breast cancer. Functional studies demonstrated that the KCNK9 gene product, TASK3, regulates mitochondrial membrane potential and apoptosis-sensitivity. In TNBC cells and non-cancerous mammary epithelial cells from high-risk women, hypomethylation of the KCNK9 DMR predicts for increased TASK3 expression and mitochondrial membrane potential (p < 0.001). This is the first identification of the KCNK9 DMR in mammary epithelial cells and demonstration that its hypomethylation in breast cancer is associated with increases in both mitochondrial membrane potential and apoptosis resistance. The high frequency of hypomethylation of the KCNK9 DMR in TNBC and non-cancerous breast tissue from high-risk women provides evidence that hypomethylation of the KNCK9 DMR/TASK3 overexpression may serve as a marker of risk and a target for prevention of TNBC, particularly in African American women.
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Affiliation(s)
- David A. Skaar
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA;
| | - Eric C. Dietze
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - Jackelyn A. Alva-Ornelas
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - David Ann
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - Dustin E. Schones
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - Terry Hyslop
- Department of Biostatistics, School of Medicine, Duke University, Durham, NC 27710, USA;
| | - Christopher Sistrunk
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - Carola Zalles
- Department of Pathology, Mercy Hospital, Miami, FL 33133, USA;
| | - Adrian Ambrose
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - Kendall Kennedy
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - Ombeni Idassi
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
| | - Gustavo Miranda Carboni
- Laboratory of Oncology, Department of Oncology, School of Medicine, University of Tennessee Health Science, Memphis, TN 38163, USA;
| | - Michael N. Gould
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI 53706, USA;
| | - Randy L. Jirtle
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA;
- Correspondence: (R.L.J.); (V.L.S.)
| | - Victoria L. Seewaldt
- Beckman Research Institute, Department of Population Sciences, City of Hope, Duarte, CA 91010, USA; (E.C.D.); (J.A.A.-O.); (D.A.); (D.E.S.); (C.S.); (A.A.); (K.K.); (O.I.)
- Correspondence: (R.L.J.); (V.L.S.)
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6
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Maguire RL, House JS, Lloyd DT, Skinner HG, Allen TK, Raffi AM, Skaar DA, Park SS, McCullough LE, Kollins SH, Bilbo SD, Collier DN, Murphy SK, Fuemmeler BF, Gowdy KM, Hoyo C. Associations between maternal obesity, gestational cytokine levels and child obesity in the NEST cohort. Pediatr Obes 2021; 16:e12763. [PMID: 33381912 PMCID: PMC8178180 DOI: 10.1111/ijpo.12763] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/25/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND Although maternal systemic inflammation is hypothesized to link maternal pre-pregnancy obesity to offspring metabolic dysfunction, patient empirical data are limited. OBJECTIVES In this study, we hypothesized that pre-pregnancy obesity alters systemic chemo/cytokines concentrations in pregnancy, and this alteration contributes to obesity in children. METHODS In a multi-ethnic cohort of 361 mother-child pairs, we measured prenatal concentrations of plasma TNF-α, IL-6, IL-8, IL-1β, IL-4, IFN-γ, IL-12 p70 subunit, and IL-17A using a multiplex ELISA and examined associations of pre-pregnancy obesity on maternal chemo/cytokine levels, and associations of these cytokine levels with offspring body mass index z score (BMI-z) at age 2-6 years using linear regression. RESULTS After adjusting for maternal smoking, ethnicity, age, and education, pre-pregnancy obesity was associated with increased concentrations of TNF-α (P = .026) and IFN-γ (P = .06). While we found no evidence for associations between TNF-α concentrations and offspring BMI-z, increased IFN-γ concentrations were associated with decreased BMI-z (P = .0002), primarily in Whites (P = .0011). In addition, increased maternal IL-17A concentrations were associated with increased BMI-z in offspring (P = .0005) with stronger associations in African Americans (P = .0042) than Whites (P = .24). CONCLUSIONS Data from this study are consistent with maternal obesity-related inflammation during pregnancy, increasing the risk of childhood obesity in an ethnic-specific manner.
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Affiliation(s)
- Rachel L. Maguire
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA,Department of Obstetrics and Gynecology, Duke University, Durham, NC, USA
| | - John S. House
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA,Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA,Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, 27709, USA
| | - Dillon T. Lloyd
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Harlyn G. Skinner
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA,Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
| | | | - Asifa Mohamed Raffi
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - David A. Skaar
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA,Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
| | - Sarah S. Park
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | | | - Scott H. Kollins
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - Staci D. Bilbo
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - David N. Collier
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA,Department of Pediatrics, Brody School of Medicine, East Carolina University, Greenville, NC, USA,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA
| | - Susan K. Murphy
- Department of Obstetrics and Gynecology, Duke University, Durham, NC, USA
| | - Bernard F. Fuemmeler
- Department of Health Behavior and Policy, Virginia Commonwealth University, Richmond, VA, USA
| | - Kymberly M. Gowdy
- Pulmonary, Critical Care and Sleep Medicine, The Ohio State University Wexner Medical Center, Davis Heart and Lung Research Institute, Columbus, Ohio, USA
| | - Cathrine Hoyo
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA,Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
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7
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Cowley M, Skaar DA, Jima DD, Maguire RL, Hudson KM, Park SS, Sorrow P, Hoyo C. Effects of Cadmium Exposure on DNA Methylation at Imprinting Control Regions and Genome-Wide in Mothers and Newborn Children. Environ Health Perspect 2018; 126:037003. [PMID: 29529597 PMCID: PMC6071808 DOI: 10.1289/ehp2085] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 01/30/2018] [Accepted: 01/30/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Imprinted genes are defined by their preferential expression from one of the two parental alleles. This unique mode of gene expression is dependent on allele-specific DNA methylation profiles established at regulatory sequences called imprinting control regions (ICRs). These loci have been used as biosensors to study how environmental exposures affect methylation and transcription. However, a critical unanswered question is whether they are more, less, or equally sensitive to environmental stressors as the rest of the genome. OBJECTIVES Using cadmium exposure in humans as a model, we aimed to determine the relative sensitivity of ICRs to perturbation of methylation compared to similar, nonimprinted loci in the genome. METHODS We assayed DNA methylation genome-wide using bisulfite sequencing of 19 newborn cord blood and 20 maternal blood samples selected on the basis of maternal blood cadmium levels. Differentially methylated regions (DMRs) associated with cadmium exposure were identified. RESULTS In newborn cord blood and maternal blood, 641 and 1,945 cadmium-associated DMRs were identified, respectively. DMRs were more common at the 15 maternally methylated ICRs than at similar nonimprinted loci in newborn cord blood (p=5.64×10-8) and maternal blood (p=6.22×10-14), suggesting a higher sensitivity for ICRs to cadmium. Genome-wide, Enrichr analysis indicated that the top three functional categories for genes that overlapped DMRs in maternal blood were body mass index (BMI) (p=2.0×10-5), blood pressure (p=3.8×10-5), and body weight (p=0.0014). In newborn cord blood, the top three functional categories were BMI, atrial fibrillation, and hypertension, although associations were not significant after correction for multiple testing (p=0.098). These findings suggest that epigenetic changes may contribute to the etiology of cadmium-associated diseases. CONCLUSIONS We analyzed cord blood and maternal blood DNA methylation profiles genome-wide at nucleotide resolution in individuals selected for high and low blood cadmium levels in the first trimester. Our findings suggest that ICRs may be hot spots for perturbation by cadmium, motivating further study of these loci to investigate potential mechanisms of cadmium action. https://doi.org/10.1289/EHP2085.
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Affiliation(s)
- Michael Cowley
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
- W.M. Keck Center for Behavioral Biology , North Carolina State University , Raleigh, North Carolina, USA
| | - David A Skaar
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
| | - Dereje D Jima
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
- Bioinformatics Research Center, North Carolina State University , Raleigh, North Carolina, USA
| | - Rachel L Maguire
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
| | - Kathleen M Hudson
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
| | - Sarah S Park
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
| | - Patricia Sorrow
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
| | - Cathrine Hoyo
- Center for Human Health and the Environment and Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina, USA
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8
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Abstract
Obesity is a complex and multifactorial disease, which likely comprises multiple subtypes. Emerging data have linked chemical exposures to obesity. As organismal response to environmental exposures includes altered gene expression, identifying the regulatory epigenetic changes involved would be key to understanding the path from exposure to phenotype and provide new tools for exposure detection and risk assessment. In this report, we summarize published data linking early-life exposure to the heavy metals, cadmium and lead, to obesity. We also discuss potential mechanisms, as well as the need for complete coverage in epigenetic screening to fully identify alterations. The keys to understanding how metal exposure contributes to obesity are improved assessment of exposure and comprehensive establishment of epigenetic profiles that may serve as markers for exposures.
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Affiliation(s)
- Sarah S Park
- Department of Biological Sciences, Center for Human Health & the Environment, North Carolina State University, Raleigh, NC 27695 USA
| | - David A Skaar
- Department of Biological Sciences, Center for Human Health & the Environment, North Carolina State University, Raleigh, NC 27695 USA
| | - Randy L Jirtle
- Department of Biological Sciences, Center for Human Health & the Environment, North Carolina State University, Raleigh, NC 27695 USA.,Department of Oncology, McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI 53705, USA.,Department of Sport & Exercise Sciences, Institute of Sport & Physical Activity Research, University of Bedfordshire, Bedford, Bedfordshire, UK
| | - Cathrine Hoyo
- Department of Biological Sciences, Center for Human Health & the Environment, North Carolina State University, Raleigh, NC 27695 USA
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Abstract
Genetic studies have been well established for identifying sequence variants associated with phenotypes. With the expanding field of epigenetics, and the growing understanding of epigenetic regulation of gene expression, similar studies can be undertaken to also define associations between epigenetic variation and phenotypes. Of particular interest are imprinted genes, which have parent-of-origin specific regulation and expression, and are key regulators of early development. Herein, we describe methods for examining epigenetic regulation by the two major hallmarks of imprinted genes: differentially methylated regions (DMRs), regulatory DNA sequences with allele specific methylation; and monoallelic expression, the silencing and transcription of opposite alleles in a parent-of-origin specific manner.
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Affiliation(s)
- David A Skaar
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA.
| | - Randy L Jirtle
- Department of Oncology, McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, 53706, USA.,Department of Sport and Exercise Sciences, Institute of Sport and Physical Activity Research (ISPAR), University of Bedfordshire, Bedford, Bedfordshire, MK41 9EA, UK
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10
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Skaar DA, Li Y, Bernal AJ, Hoyo C, Murphy SK, Jirtle RL. The human imprintome: regulatory mechanisms, methods of ascertainment, and roles in disease susceptibility. ILAR J 2014; 53:341-58. [PMID: 23744971 DOI: 10.1093/ilar.53.3-4.341] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Imprinted genes form a special subset of the genome, exhibiting monoallelic expression in a parent-of-origin-dependent fashion. This monoallelic expression is controlled by parental-specific epigenetic marks, which are established in gametogenesis and early embryonic development and are persistent in all somatic cells throughout life. We define this specific set of cis-acting epigenetic regulatory elements as the imprintome, a distinct and specially tasked subset of the epigenome. Imprintome elements contain DNA methylation and histone modifications that regulate monoallelic expression by affecting promoter accessibility, chromatin structure, and chromatin configuration. Understanding their regulation is critical because a significant proportion of human imprinted genes are implicated in complex diseases. Significant species variation in the repertoire of imprinted genes and their epigenetic regulation, however, will not allow model organisms solely to be used for this crucial purpose. Ultimately, only the human will suffice to accurately define the human imprintome.
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Affiliation(s)
- David A Skaar
- Department of Oncology, Duke University Medical Center, Durham, North Carolina, USA
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Bernal AJ, Dolinoy DC, Huang D, Skaar DA, Weinhouse C, Jirtle RL. Adaptive radiation-induced epigenetic alterations mitigated by antioxidants. FASEB J 2012; 27:665-71. [PMID: 23118028 DOI: 10.1096/fj.12-220350] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Humans are exposed to low-dose ionizing radiation (LDIR) from a number of environmental and medical sources. In addition to inducing genetic mutations, there is concern that LDIR may also alter the epigenome. Such heritable effects early in life can either be positively adaptive or result in the enhanced formation of diseases, including cancer, diabetes, and obesity. Herein, we show that LDIR significantly increased DNA methylation at the viable yellow agouti (A(vy)) locus in a sex-specific manner (P=0.004). Average DNA methylation was significantly increased in male offspring exposed to doses between 0.7 and 7.6 cGy, with maximum effects at 1.4 and 3.0 cGy (P<0.01). Offspring coat color was concomitantly shifted toward pseudoagouti (P<0.01). Maternal dietary antioxidant supplementation mitigated both the DNA methylation changes and coat color shift in the irradiated offspring. Thus, LDIR exposure during gestation elicits epigenetic alterations that lead to positive adaptive phenotypic changes that are negated with antioxidants, indicating they are mediated in part by oxidative stress. These findings provide evidence that in the isogenic A(vy) mouse model, epigenetic alterations resulting from LDIR play a role in radiation hormesis, bringing into question the assumption that every dose of radiation is harmful.
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Affiliation(s)
- Autumn J Bernal
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina,, USA
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12
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Stone JL, McMillan RE, Skaar DA, Bradshaw JM, Jirtle RL, Sikes ML. DNA double-strand breaks relieve USF-mediated repression of Dβ2 germline transcription in developing thymocytes. J I 2012; 188:2266-75. [PMID: 22287717 DOI: 10.4049/jimmunol.1002931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of germline promoters is central to V(D)J recombinational accessibility, driving chromatin remodeling, nucleosome repositioning, and transcriptional read-through of associated DNA. We have previously shown that of the two TCRβ locus (Tcrb) D segments, Dβ1 is flanked by an upstream promoter that directs its transcription and recombinational accessibility. In contrast, transcription within the DJβ2 segment cluster is initially restricted to the J segments and only redirected upstream of Dβ2 after D-to-J joining. The repression of upstream promoter activity prior to Tcrb assembly correlates with evidence that suggests DJβ2 recombination is less efficient than that of DJβ1. Because inefficient DJβ2 assembly offers the potential for V-to-DJβ2 recombination to rescue frameshifted V-to-DJβ1 joints, we wished to determine how Dβ2 promoter activity is modulated upon Tcrb recombination. In this study, we show that repression of the otherwise transcriptionally primed 5'Dβ2 promoter requires binding of upstream stimulatory factor (USF)-1 to a noncanonical E-box within the Dβ2 12-recombination signal sequence spacer prior to Tcrb recombination. USF binding is lost from both rearranged and germline Dβ2 sites in DNA-dependent protein kinase, catalytic subunit-competent thymocytes. Finally, genotoxic dsDNA breaks lead to rapid loss of USF binding and gain of transcriptionally primed 5'Dβ2 promoter activity in a DNA-dependent protein kinase, catalytic subunit-dependent manner. Together, these data suggest a mechanism by which V(D)J recombination may feed back to regulate local Dβ2 recombinational accessibility during thymocyte development.
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Affiliation(s)
- Jennifer L Stone
- Department of Microbiology, North Carolina State University, Raleigh, NC 27695, USA
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Abstract
Differentially methylated regions (DMRs) are stable epigenetic features within or in proximity to imprinted genes. We used this feature to identify candidate human imprinted loci by quantitative DNA methylation analysis. We discovered a unique DMR at the 5′-end of FAM50B at 6p25.2. We determined that sense transcripts originating from the FAM50B locus are expressed from the paternal allele in all human tissues investigated except for ovary, in which expression is biallelic. Furthermore, an antisense transcript, FAM50B-AS, was identified to be monoallelically expressed from the paternal allele in a variety of tissues. Comparative phylogenetic analysis showed that FAM50B orthologs are absent in chicken and platypus, but are present and biallelically expressed in opossum and mouse. These findings indicate that FAM50B originated in Therians after divergence from Prototherians via retrotransposition of a gene on the X chromosome. Moreover, our data are consistent with acquisition of imprinting during Eutherian evolution after divergence of Glires from the Euarchonta mammals. FAM50B expression is deregulated in testicular germ cell tumors, and loss of imprinting occurs frequently in testicular seminomas, suggesting an important role for FAM50B in spermatogenesis and tumorigenesis. These results also underscore the importance of accounting for parental origin in understanding the mechanism of 6p25-related diseases.
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Affiliation(s)
- Aiping Zhang
- Department of Radiation Oncology, Department of Community and Family Medicine and Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC 27710, USA
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Cukier HN, Skaar DA, Rayner-Evans MY, Konidari I, Whitehead PL, Jaworski JM, Cuccaro ML, Pericak-Vance MA, Gilbert JR. Identification of chromosome 7 inversion breakpoints in an autistic family narrows candidate region for autism susceptibility. Autism Res 2010; 2:258-66. [PMID: 19877165 DOI: 10.1002/aur.96] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Chromosomal breaks and rearrangements have been observed in conjunction with autism and autistic spectrum disorders. A chromosomal inversion has been previously reported in autistic siblings, spanning the region from approximately 7q22.1 to 7q31. This family is distinguished by having multiple individuals with autism and associated disabilities. The region containing the inversion has been strongly implicated in autism by multiple linkage studies, and has been particularly associated with language defects in autism as well as in other disorders with language components. Mapping of the inversion breakpoints by FISH has localized the inversion to the region spanning approximately 99-108.75 Mb of chromosome 7. The proximal breakpoint has the potential to disrupt either the coding sequence or regulatory regions of a number of cytochrome P450 genes while the distal region falls in a relative gene desert. Copy number variant analysis of the breakpoint regions detected no duplication or deletion that could clearly be associated with disease status. Association analysis in our autism data set using single nucleotide polymorphisms located near the breakpoints showed no significant association with proximal breakpoint markers, but has identified markers near the distal breakpoint ( approximately 108-110 Mb) with significant associations to autism. The chromosomal abnormality in this family strengthens the case for an autism susceptibility gene in the chromosome 7q22-31 region and targets a candidate region for further investigation.
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Affiliation(s)
- Holly N Cukier
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, USA
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15
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Ashley-Koch AE, Jaworski J, Ma DQ, Mei H, Ritchie MD, Skaar DA, Robert Delong G, Worley G, Abramson RK, Wright HH, Cuccaro ML, Gilbert JR, Martin ER, Pericak-Vance MA. Investigation of potential gene–gene interactions between apoe and reln contributing to autism risk. Psychiatr Genet 2007; 17:221-6. [PMID: 17621165 DOI: 10.1097/ypg.0b013e32809c2f75] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Several candidate gene studies support RELN as susceptibility gene for autism. Given the complex inheritance pattern of autism, it is expected that gene-gene interactions will exist. A logical starting point for examining potential gene-gene interactions is to evaluate the joint effects of genes involved in a common biological pathway. RELN shares a common biological pathway with APOE, and Persico et al. have observed transmission distortion of the APOE-2 allele in autism families. OBJECTIVE We evaluated RELN and APOE for joint effects in autism susceptibility. METHODS A total of 470 Caucasian autism families were analyzed (265 multiplex; 168 trios with no family history; 37 positive family history but only one sampled affected). These families were genotyped for 11 RELN polymorphisms, including the 5' untranslated region repeat previously associated with autism, as well as for the APOE functional allele. We evaluated single locus allelic and genotypic association with the pedigree disequilibrium test and geno-PDT, respectively. Multilocus effects were evaluated using the extended version of the multifactorial dimensionality reduction method. RESULTS For the single locus analyses, there was no evidence for an effect of APOE in our data set. Evidence for association with RELN (rs2,073,559; trio subset P=0.07 PDT; P=0.001 geno-PDT; overall geno-PDT P=0.05), however, was found. For multilocus geno-PDT analysis, the joint genotype of APOE and RELN rs2,073,559 was highly significant (trio subset, global P=0.0001), probably driven by the RELN single locus effect. Using the extended version of the multifactorial dimensionality reduction method to detect multilocus effects, there were no statistically significant associations for any of the n-locus combinations involving RELN or APOE in the overall or multiplex subset. In the trio subset, 1-locus and 2-locus models selected only markers in RELN as best models for predicting autism case status. CONCLUSION Thus, we conclude that there is no main effect of APOE in our autism data set, nor is there any evidence for a joint effect of APOE with RELN. RELN, however, remains a good candidate for autism susceptibility.
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Affiliation(s)
- Allison E Ashley-Koch
- Center for Human Genetics, Department of Medicine, Duke University Medical Center, Snyderman Genomic Sciences Building, Durham, NC 27710, USA.
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Skaar DA, Shao Y, Haines JL, Stenger JE, Jaworski J, Martin ER, DeLong GR, Moore JH, McCauley JL, Sutcliffe JS, Ashley-Koch AE, Cuccaro ML, Folstein SE, Gilbert JR, Pericak-Vance MA. Analysis of the RELN gene as a genetic risk factor for autism. Mol Psychiatry 2005; 10:563-71. [PMID: 15558079 DOI: 10.1038/sj.mp.4001614] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Several genome-wide screens have indicated the presence of an autism susceptibility locus within the distal long arm of chromosome 7 (7q). Mapping at 7q22 within this region is the candidate gene reelin (RELN). RELN encodes a signaling protein that plays a pivotal role in the migration of several neuronal cell types and in the development of neural connections. Given these neurodevelopmental functions, recent reports that RELN influences genetic risk for autism are of significant interest. The total data set consists of 218 Caucasian families collected by our group, 85 Caucasian families collected by AGRE, and 68 Caucasian families collected at Tufts University were tested for genetic association of RELN variants to autism. Markers included five single-nucleotide polymorphisms (SNPs) and a repeat in the 5'-untranslated region (5'-UTR). Tests for association in Duke and AGRE families were also performed on four additional SNPs in the genes PSMC2 and ORC5L, which flank RELN. Family-based association analyses (PDT, Geno-PDT, and FBAT) were used to test for association of single-locus markers and multilocus haplotypes with autism. The most significant association identified from this combined data set was for the 5'-UTR repeat (PDT P-value=0.002). These analyses show the potential of RELN as an important contributor to genetic risk in autism.
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Affiliation(s)
- D A Skaar
- Department of Medicine, Center for Human Genetics, IGSP, Duke University Medical Center, Durham, NC, USA
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Abstract
There are several kinases in Saccharomyces cerevisiae that phosphorylate the CTD of RNA polymerase II, but specific and distinct functions of the phospho-CTDs generated by the different kinases are not well understood. A genetic screen for suppressors of loss of yeast CTD kinase I (CTDK-I) function (by deletion of the catalytic subunit gene CTK1) identified PTI1, a potential 3' cleavage/polyadenylation factor. Genetic and physical interactions connect Pti1p to components of CF IA and CF II/CPF, and mutations of PTI1 or CTK1 affect 3' cleavage site choice and transcript abundance of particular genes. Therefore, one important function of the CTDK-I-generated phospho-CTD appears to be the coupling of transcription to 3' processing of pre-mRNAs by a Pti1p-containing complex.
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Affiliation(s)
- David A Skaar
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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Kieft TL, White CS, Loftin SR, Aguilar R, Craig JA, Skaar DA. Temporal Dynamics in Soil Carbon and Nitrogen Resources at a Grassland-Shrubland Ecotone. Ecology 1998. [DOI: 10.2307/176962] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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