로그인

Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying DNA sequence, but instead by the chromatin organization and histone variants. Once established, the centromere organization and functions remain stably inherited through several cell divisions.

Histones are central to epigenetic inheritance

In the nucleosome, both DNA and histones are chemically modified. DNA is methylated at cytosine residues, and histones are methylated, acetylated, or phosphorylated. Each of these modifications constitutes a signal called histone code. Recent advances highlight methylation as a bona fide epigenetic mark, and chromatin complexity as the primary carrier of epigenetic marks. The presence of histone variants at specific locations and time increases the complexity of chromatin organization. For example, the histone H3 variant CENP-A is incorporated into a nucleosome in a DNA synthesis-independent manner, resulting in an unusually stable nucleosome.

Inheritance of histones

The DNA methylation, deposition of histones on DNA strands, and post-translational modifications of histones or histone code are connected to replication machinery. PCNA, a DNA processivity factor, is the vital protein that links DNA replication with the inheritance of epigenetic marks. At the replication fork, the nucleosomes are displaced such that H2A-H2B dimers are entirely removed from the replication fork. The parental H3-H4 tetramers are then distributed to daughter strands followed by the placement of newly synthesized histone subunits on parental histones to complete the nucleosomes.

Tags
Chromatin StructuresSomatic CellsLiver CellsSkin CellsGene Expression PatternsEpigenetic InheritanceCentromereHeterochromatinEuchromatinHistone ModificationsTissue Specific PhenotypesDNA ReplicationHistone OctamerCENP A Histones

장에서 5:

article

Now Playing

5.17 : 염색질 구조의 유전

DNA와 염색체 구조

6.0K Views

article

5.1 : DNA 포장

DNA와 염색체 구조

29.8K Views

article

5.2 : 유전자적 주형으로서의 DNA

DNA와 염색체 구조

21.2K Views

article

5.3 : 유전자의 구성

DNA와 염색체 구조

11.8K Views

article

5.4 : 염색체 구조

DNA와 염색체 구조

22.1K Views

article

5.5 : 염색체 복제

DNA와 염색체 구조

8.5K Views

article

5.6 : 뉴클레오솜

DNA와 염색체 구조

15.6K Views

article

5.7 : 뉴클레오솜 중심입자

DNA와 염색체 구조

11.6K Views

article

5.8 : 뉴클레오솜 리모델링

DNA와 염색체 구조

8.7K Views

article

5.9 : 염색질 포장

DNA와 염색체 구조

14.8K Views

article

5.10 : 핵형분석

DNA와 염색체 구조

10.0K Views

article

5.11 : 위치효과얼룩

DNA와 염색체 구조

6.2K Views

article

5.12 : 히스톤 변형

DNA와 염색체 구조

12.6K Views

article

5.13 : 염색질 변형의 확산

DNA와 염색체 구조

8.0K Views

article

5.14 : 램프브러시염색체

DNA와 염색체 구조

7.8K Views

See More

JoVE Logo

개인 정보 보호

이용 약관

정책

연구

교육

JoVE 소개

Copyright © 2025 MyJoVE Corporation. 판권 소유