Hey Jeff, do you know what you are made of? You are made of cells that contain your DNA!! A Histone (protein) plus DNA makes what is called a nucleosome. Nucleosomes are what make up your genes.
Wow Gus!! That's awesome :) thanks for telling me that. So how exactly are these genes regulated?
Well, the histone proteins are able to pack and unpack regions of your DNA. If they are tightly packed it's called heterochromatin, and if its loosely packed, it's called euchormatin.
Well, I'm a bit confused. What does this packing do?
Well, there are two regulatory systems. The first is called the acetylation system. This loosens DNA by adding acetyl grps and lysine into the histone tail. This neutralizes the charge and causes for looser packing.
So Im guessing in the next system, the DNA is tightly packed?
You are exactly right. The next system is the methylation system which packs in the DNA really close. This causes for less transcription leading to less access to the promoter to transcribe the DNA to make it into a gene.
So these uses of packing are helped to regulation gene expression?
Exactly! You got it. Tightly packed (methylation) DNA leads to less access to the gene to transcribe it into a protein, while loosely packed (acetylation) DNA gives more access to a gene allowing it to transcribe easier to make a protein.
Thanks so much Gus! Now I know how my body functions :)
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