PACKAGING OF DNA IN EUKARYOTS

Packaging of DNA in Eukaryotes

1. DNA is packaged in the nucleus as a nucleoprotein complex called chromatin

2. Levels of chromatin packaging:

(a) Nucleosomes: ~200 bp DNA and histones

(i) nucleosome core particles consist of ~140 bp of DNA wrapped around a

protein octamer consisting of 2 subunits each of histones H2A, H2B, H3,

and H4

(ii) linker DNA is the DNA between two core particles; histone H1 binds to the

linker DNA and the core particle

(b) 30 nm fiber (Solenoid): nucleosomes are wound into a solenoid-like structure—

requires histone H1 binding to every linker DNA

3. chromatin is the template for replication and transcription and the substrate for

DNA repair and recombination


THANKS FOR VISITING ALL SCIENCESS