DNA Packaging

Heterochromatin

Densely packed, transcriptionally inactive DNA

Euchromatin

Loosely packed, transcriptionally active DNA

Telomeres

Repetitive DNA sequences at chromosome ends that protect against degradation

Centromeres

Specialized region for spindle attachment during cell division

Replication origins

Sites where DNA replication starts

Nucleosomes

DNA wrapped around a histone octamer

Chromatin fibers

Higher-order structures formed by nucleosome compaction

Histone proteins

Core histones H2A, H2B, H3, and H4 form the nucleosome core

Condensin I & II

Help condense chromosomes during mitosis

Cohesins

Hold sister chromatids together until anaphase

Histone PTMs

Chemical modifications such as acetylation and methylation that regulate DNA accessibility

ATP-dependent chromatin remodeling complexes

Use energy to reposition nucleosomes for transcription regulation

Reader-writer complexes

Spread histone modifications to neighboring nucleosomes

Barrier DNA

Blocks the spread of histone modifications to specific regions

Chromatin replication

Histone chaperones and remodeling complexes ensure both DNA sequence and chromatin structure are duplicated accurately