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CpXpGメチル化を維持するために,クロモメチラーゼ3の必要性
A M Lindroth1, X Cao, J P Jackson
1Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA.
まとめ
アラビドプシス SUPERMANのロカスサイレンシングは,非正規のサイトシンでの濃厚なハイパーメチル化を含みます. CHROMOMETHYLASE3 (CMT3) の機能喪失変異は,このメチル化を減少させ,遺伝子発現を再活性化し,CMT3を明らかにします.
科学分野:
- 植物分子生物学 植物分子生物学
- エピジェネティクス エピジェネティクス
- 遺伝学 遺伝学とは
背景:
- アラビドプシス・スーパーマン (SUP) ローカスは,非正規のサイトシン (CpXpGおよび非対称サイト) で濃厚なハイパーメチル化によって表遺伝的静止を呈する.
- この表遺伝子静止を維持するメカニズムの理解は,植物の発達と遺伝子調節に不可欠です.
研究 の 目的:
- 静止されたアラビドプシスSUPの位置で非正規のサイトシンメチレーションを維持する遺伝子を特定する.
- エピジェネティック遺伝子サイレンシングにおける新型メチルトランスファーゼの役割を明らかにする.
主な方法:
- SUP.の超メチラ化クラーク・ケント変異アレルの抑制剤を特定するために,遺伝子スクリーンを用いた.
- CHROMOMETHYLASE3 (CMT3) の機能喪失アレルが特定され,特徴づけられました.
- SUP遺伝子と他のゲノム配列のCpXpGメチル化レベルは,cmt3変異体で分析されました.
- 固有のレトロトランスポゾン発現は,cmt3変異体においてモニタリングされた.
主要な成果:
- 新型サイトシンメチルトランスフェラーゼホモログであるCHROMOMETHYLASE3 (CMT3) の9つの機能喪失アレルは,抑制剤として特定されました.
- cmt3変異体は,SUP遺伝子および全ゲノムでのCpXpGメチル化の低下を示した.
- cmt3変異体において,内生レトロトランポゾンの再活性化が観察された.
- メチル化変化にもかかわらず,cmt3変異体は野生型の形態を示した.
結論:
- CHROMOMETHYLASE3 (CMT3) はCpG以外のDNAメチルトランスフェラーゼで,表遺伝子の遺伝子サイレンシングを維持する役割を担っています.
- CMT3は,ゲノム全体のメチル化パターンと移植可能な元素の調節に重要な役割を果たしています.
- CMT3をターゲットにすることは,植物における表遺伝的沈黙を操作するための潜在的な戦略を提供します.
関連する概念動画
Epigenetic Regulation
Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Cell Specific Gene Expression
Multicellular organisms contain a variety of structurally and functionally distinct cell types, but the DNA in all the cells originated from the same parent cells. The differences in the cells can be attributed to the differential gene expression. Liver cells, whose functions include detoxification of blood, production of bile to metabolize fats, and synthesis of proteins essential for metabolism, must express a specific set of genes to perform their functions. Gene expression also varies with...
Chromatin Immunoprecipitation- ChIP
Chromatin immunoprecipitation, or ChIP, is an antibody-based technique used to identify sites on DNA that bind to transcription factors of interest or histone proteins. It also helps determine the type of histone modifications such as acetylation, phosphorylation, or methylation.
Types of ChIP
ChIP can be divided into two types - X-ChIP and N-ChIP. X-ChIP involves in vivo cross-linking of histones and regulatory proteins to DNA, fragmenting the DNA by sonication, and isolating the protein-DNA...
Types of ChIP
ChIP can be divided into two types - X-ChIP and N-ChIP. X-ChIP involves in vivo cross-linking of histones and regulatory proteins to DNA, fragmenting the DNA by sonication, and isolating the protein-DNA...
Heterochromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...

