Reference no: EM132671654

DNA packaging and DNA replication

We have a lot of DNA in our bodies - enough to reach to the sun and back about 300 times! How do we fit all that DNA in our cells' nuclei?

DNA is packaged into chromatin - it is wound around protein complexes known as histones. Learn more about how this phenomena occurs and how it can result in compacted DNA here: https://www.nature.com/scitable/topicpage/dna-packaging-nucleosomes-and-chromatin-310/

While chromatin helps us compact our DNA so it can fit inside our cells, it poses a challenge to the DNA replication machinery. Currently, this is an area of research in my lab and others, with the goal of understanding how chromatin influences aspects of DNA replication and how histones are re-established in replicated DNA.

Using what you already learned about DNA replication and what you now know about histones, answer the following questions.

1. Describe how DNA packaging (DNA wrapped around histones to form chromatin) might be a challenge for DNA replication. In what steps would the presence of nucleosomes interfere with replication?

2. How could chromatin remodeling enzymes help DNA replication proceed? Describe 1-2 possible mechanisms.

3. Newly replicated DNA also needs to be packaged into chromatin. Provide some ideas of how newly replicated DNA could get histones.

4. Histones often hold information by getting different modifications at specific genes, which tells the cell whether a gene should be "on" (get transcribed to RNA) or "off" (see the Mini-Lecture from this week where I discuss how my research relates to this at the beginning of the video). How do you think this information could be maintained during DNA replication? Discuss 1-2 ideas.