Genome-wide analysis identifies changes in histone retention and epigenetic modifications at developmental and imprinted gene loci in the sperm of infertile men
Genome-wide analysis identifies changes in histone retention and epigenetic modifications at developmental and imprinted gene loci in the sperm of infertile men
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DOI：
10.1093/humrep/der192
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发表时间：
2011-09-01
影响因子：
6.1
通讯作者：
Carrell, Douglas T.
中科院分区：
文献类型：
--
作者：
Hammoud, Saher Sue;Nix, David A.;Carrell, Douglas T.
背景：可育男性的精子染色质保留少量核小体，这些核小体在发育基因启动子和印迹基因位点富集。这种独特的染色质包装在某些基因启动子提供了这些基因组位点的能力，将有指导意义的表观遗传信息传递给受精卵，潜在地扩大精子表观基因组在胚胎发生中的作用和意义。我们假设染色质包装的变化可能与生殖结果不良有关。方法：招募7例生殖功能障碍患者：3例在体外受精过程中原因不明的胚胎发生不良，4例诊断为男性不育症，先前显示有蛋白化改变。通过分离和纯化与组蛋白和蛋白蛋白结合的DNA，对组蛋白和组蛋白修饰的位置进行全基因组分析。使用高通量测序对DNA的组蛋白结合部分进行分析，包括最初和随后的染色质免疫沉淀。将蛋白结合部分与agilent阵列杂交。采用亚硫酸盐测序法检测DNA甲基化。结果：与可育男性不同，7名不育男性中有5名具有非程序性（随机分布）组蛋白全基因组保留。有趣的是，与总组蛋白库相比，不育男性配子中H3赖氨酸4甲基化（H3K4me）或H3赖氨酸27甲基化（H3K27me）的定位与可育男性高度相似。然而，在发育转录因子和某些印迹基因中保留的H3K4me或H3K27me数量有所减少。最后，在一部分不育男性中，候选发育启动子和印迹位点的甲基化状态发生了改变。结论：这项对不育男性精子表观遗传标记的初步全基因组分析表明，与可育男性相比，不育男性精子在组成和表观遗传标记上存在差异，特别是在某些印迹和发育位点上。虽然没有单个基因座显示出染色质包装或DNA修饰的完全改变，但数据表明，整个基因组存在适度的变化，并可能对繁殖力产生累积的有害影响。
BACKGROUND: The sperm chromatin of fertile men retains a small number of nucleosomes that are enriched at developmental gene promoters and imprinted gene loci. This unique chromatin packaging at certain gene promoters provides these genomic loci the ability to convey instructive epigenetic information to the zygote, potentially expanding the role and significance of the sperm epigenome in embryogenesis. We hypothesize that changes in chromatin packaging may be associated with poor reproductive outcome.METHODS: Seven patients with reproductive dysfunction were recruited: three had unexplained poor embryogenesis during IVF and four were diagnosed with male infertility and previously shown to have altered protamination. Genome-wide analysis of the location of histones and histone modifications was analyzed by isolation and purification of DNA bound to histones and protamines. The histone-bound fraction of DNA was analyzed using high-throughput sequencing, both initially and following chromatin immunoprecipitation. The protamine-bound fraction was hybridized to agilent arrays. DNA methylation was examined using bisulfite sequencing.RESULTS: Unlike fertile men, five of seven infertile men had non-programmatic (randomly distributed) histone retention genome-wide. Interestingly, in contrast to the total histone pool, the localization of H3 Lysine 4 methylation (H3K4me) or H3 Lysine 27 methylation (H3K27me) was highly similar in the gametes of infertile men compared with fertile men. However, there was a reduction in the amount of H3K4me or H3K27me retained at developmental transcription factors and certain imprinted genes. Finally, the methylation status of candidate developmental promoters and imprinted loci were altered in a subset of the infertile men.CONCLUSIONS: This initial genome-wide analysis of epigenetic markings in the sperm of infertile men demonstrates differences in composition and epigenetic markings compared with fertile men, especially at certain imprinted and developmental loci. Although no single locus displays a complete change in chromatin packaging or DNA modification, the data suggest that moderate changes throughout the genome exist and may have a cumulative detrimental effect on fecundity.