まとめ
研究者らは,典型的な繰り返し単位が欠けているヒトヒストン遺伝子のクラスタを特定した. この独特のゲノム組織は,哺乳類の発達初期におけるヒストン合成の必要性が減少していることと関係している可能性があります.
科学分野:
- ゲノミクスゲノミクスとは
- 分子生物学は分子生物学である.
- 発達生物学 発達生物学とは
背景:
- ヒストン遺伝子はDNAの包装と遺伝子調節に不可欠です.
- 以前の研究では,様々な種におけるヒストン遺伝子組織を特徴づけた.
研究 の 目的:
- 人間のヒストン遺伝子を分離し,特徴づけること.
- 人間のヒストン遺伝子のゲノム組織を決定する.
主な方法:
- Xenopus laevis histone H4 cDNAプローブを使用してヒトゲノムDNAライブラリをスクリーニングする.
- ゲノムクローンのマッピングと,ヒトヒストンmRNAのブラットハイブリダイゼーションとハイブリダイゼーション選択による遺伝子位置の決定.
主要な成果:
- ヒストンのヒト遺伝子を含む5つのクローンが分離されました.
- 人間のヒストン遺伝子はクラスター化されていますが,以前に特徴づけられたヒストン遺伝子とは異なり,認識可能な繰り返すユニットがありません.
- この組織は,他の種に見られるタンデム繰り返しと大きく異なっています.
結論:
- 人間のゲノムは,ヒストン遺伝子のユニークで,より組織的な配列を示しています.
- このゲノム構造は,哺乳類の発達中のヒストン遺伝子発現に対する進化的適応を反映している可能性がある.
関連する概念動画
02:33The Nucleosome
DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside the nucleus is astonishing. It is organized into several sequentially higher levels of compaction to fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
02:30Histone Variants at the Centromere
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3 variants are also...
02:05Duplication of Chromatin Structure
The process of chromosome duplication during cell division requires genome-wide disruption and re-assembly of chromatin. The chromatin structure must be accurately inherited, reassembled, and maintained in the daughter cells to ensure lineage propagation.
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
02:38Heterochromatin
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...
02:33The Nucleosome
DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside the nucleus is astonishing. It is organized into several sequentially higher levels of compaction to fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
01:19The Nucleosome
Human DNA is almost two meters long. However, it is compressed inside a tiny nucleus measuring only a few microns in diameter. To make this degree of compaction possible, DNA is organized into several sequential levels so that it can fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...