AAT Bioquest

How is DNA packaged in a cell?

Posted January 23, 2023


DNA is packed in a cell through the assistance of histones. The histones are used as the proteins for the DNA to be coiled around. The entire structure becomes known as a nucleosome, which includes a histone octamer and 146 to 147 base pairs of DNA. Histones are positively charged proteins that actively adhere to negatively charged DNA molecules and form complexes known as nucleosomes. Each nucleosome is made out of DNA that is wound 1.65 times around 8 histones. Next, the nucleosomes and the linker DNA between them are coiled into a 30-nm solenoid chromatin fiber through scaffolding proteins . This coiling shorterns the chromosome so that it becomes approximately 50 times shorter than its extender form. Then, a variety of fibrous proteins are used to pack the chromatin. These proteins ensure that each chromosome in a non-dividing cell moves to a specific area of the nucleus that doesn't overlap with other chromosomes. To simplify, DNA packaging is broken down into 3 orders: nucleosomes are first-order DNA packing, solidein fiber is a type of second-order DNA packing, and the third order is scaffold loop chromatids chromosomes.

Additional resources

Chromosome and Chromatin

DNA and RNA Quantitation

6-ROX glycine *25 uM fluorescence reference solution for PCR reactions*

Helixyte™ Green *10,000X Aqueous PCR Solution*