2013年11月13日訊 /生物谷BIOON/--近日,發表於American Journal of Human Genetics雜誌上的一項研究首次深入分析脂肪細胞中DNA甲基化過程,DNA甲基化是影響基因調控的過程。研究DNA甲基化對於了解與代謝性疾病發病相關的基因區域是至關重要的。
該小組研究來自雙胞胎的脂肪細胞的基因組,發現DNA甲基化模式很可能會從父母遺傳下來,遺傳給孩子。這項研究可以幫助弄清多少DNA甲基化模式的變化是遺傳方面引起的,又有多少是由於環境因素所引發的。雙胞胎從出生時基因完全相同,後期疾病發展出現差異可能是由於環境因素的影響。DNA甲基化是一種表觀遺傳變化,往往受到遺傳控制。DNA甲基化的最常見形式涉及添加甲基組到DNA鹼基半胱氨酸上。這個過程對於調節許多細胞過程,如胚胎發育,轉錄和染色質結構是非常重要的。由於DNA甲基化的重要角色,越來越多研究發現人類疾病與DNA甲基化異常相關。
Panos Deloukas教授說:我們正在探索人類表觀遺傳的變異,試圖理解基因表達和DNA甲基化之間的相互作用,以及兩者相互作用如何影響疾病的發生。我們的研究發現甲基化和代謝疾病相關脂肪組織中的基因區域之間存在許多聯繫。
該小組調查了648對雙胞胎脂肪組織樣品基因組中超過450,000個基因位點,他們發現,健康的人很少有甲基化模式的變化,在調控基因表達的重要區域如啟動子中,基因變異被抑制。
當Panos Deloukas教授團隊將遺傳變異和DNA甲基化結合起來分析,他們發現有28%的位點受遺傳控制,只有6%的遺傳變異調控基因表達和DNA甲基化。Panos Deloukas教授團隊將獲得的信息與DNA甲基化、來自NIH RoadMap Epigenomics Mapping Consortium的其他遺傳數據以及所有已知與常見疾病相關的基因組區域研究數據整合。他們發現許多調節DNA甲基化的遺傳變異在調控元件即基因增強子中發生重疊。
Elin Grundberg說:我們知道DNA甲基化在基因調控和疾病易感性中起到了重要作用,通過我們的研究,我們開始解開DNA甲基化變化的頻率、位置和影響。這項研究將提供與代謝疾病發病相關的基因區域的功能信息,這項研究大大提高理解甲基化和疾病之間的聯繫。(生物谷Bioon.com)
Global Analysis of DNA Methylation Variation in Adipose Tissue from Twins Reveals Links to Disease-Associated Variants in Distal Regulatory Elements
Elin Grundberg, Eshwar Meduri, Johanna K. Sandling, sa K. Hedman, Sarah Keildson, Alfonso Buil, Stephan Busche, Wei Yuan, James Nisbet, Magdalena Sekowska, Alicja Wilk, Amy Barrett, Kerrin S. Small, Bing Ge, Maxime Caron, So-Youn Shin, the Multiple Tissue Human Expression Resource Consortium, Mark Lathrop, Emmanouil T. Dermitzakis, Mark I. McCarthy, Timothy D. Spector2 Jordana T. Bell, and Panos Deloukas
Epigenetic modifications such as DNA methylation play a key role in gene regulation and disease susceptibility. However, little is known about the genome-wide frequency, localization, and function of methylation variation and how it is regulated by genetic and environmental factors. We utilized the Multiple Tissue Human Expression Resource (MuTHER) and generated Illumina 450K adipose methylome data from 648 twins. We found that individual CpGs had low variance and that variability was suppressed in promoters. We noted that DNA methylation variation was highly heritable (h2median = 0.34) and that shared environmental effects correlated with metabolic phenotype-associated CpGs. Analysis of methylation quantitative-trait loci (metQTL) revealed that 28% of CpGs were associated with nearby SNPs, and when overlapping them with adipose expression quantitative-trait loci (eQTL) from the same individuals, we found that 6% of the loci played a role in regulating both gene expression and DNA methylation. These associations were bidirectional, but there were pronounced negative associations for promoter CpGs. Integration of metQTL with adipose reference epigenomes and disease associations revealed significant enrichment of metQTL overlapping metabolic-trait or disease loci in enhancers (the strongest effects were for high-density lipoprotein cholesterol and body mass index [BMI]). We followed up with the BMI SNP rs713586, a cg01884057 metQTL that overlaps an enhancer upstream of ADCY3, and used bisulphite sequencing to refine this region. Our results showed widespread population invariability yet sequence dependence on adipose DNA methylation but that incorporating maps of regulatory elements aid in linking CpG variation to gene regulation and disease risk in a tissue-dependent manner.