Children's Hospital Oakland Research Institute, Oakland, California 94609, USA;
Genome Res. 2014 May;24(5):821-30. doi: 10.1101/gr.162412.113. Epub 2014 Feb 20.
Cytosine methylation in the genome of Drosophila melanogaster has been elusive and controversial: Its location and function have not been established. We have used a novel and highly sensitive genomewide cytosine methylation assay to detect and map genome methylation in stage 5 Drosophila embryos. The methylation we observe with this method is highly localized and strand asymmetrical, limited to regions covering ∼1% of the genome, dynamic in early embryogenesis, and concentrated in specific 5-base sequence motifs that are CA- and CT-rich but depleted of guanine. Gene body methylation is associated with lower expression, and many genes containing methylated regions have developmental or transcriptional functions. The only known DNA methyltransferase in Drosophila is the DNMT2 homolog MT2, but lines deficient for MT2 retain genomic methylation, implying the presence of a novel methyltransferase. The association of methylation with a lower expression of specific developmental genes at stage 5 raises the possibility that it participates in controlling gene expression during the maternal-zygotic transition.
其位置和功能尚未确定。我们使用了一种新颖且高度敏感的全基因组胞嘧啶甲基化检测方法，以检测和绘制 5 期果蝇胚胎中的基因组甲基化图谱。我们通过该方法观察到的甲基化高度局限且链不对称，仅限于约占基因组 1%的区域，在早期胚胎发生中具有动态性，并且集中在特定的富含 CA 和 CT 但不含鸟嘌呤的 5 碱基序列基序中。基因体甲基化与表达水平降低有关，许多含有甲基化区域的基因具有发育或转录功能。果蝇中唯一已知的 DNA 甲基转移酶是 DNMT2 同源物 MT2，但缺乏 MT2 的品系仍保留基因组甲基化，这表明存在一种新型的甲基转移酶。在第 5 期，甲基化与特定发育基因表达水平降低的关联提出了这样一种可能性，即它可能参与了母-合子过渡期间的基因表达调控。
