First Chromatin Model

biology

The structure of the chromatin has been a long sought after goal of biologists. Every cell contains a central region, called the nucleus, which contains all of your DNA. This code is not all alone inside; it is all wrapped up and bonded with histones (proteins that specifically bond DNA together) in a complex called a nucleosome. The nucleosomes are then wrapped together with another histone protein, then with scaffold proteins which basically act like power outlet adaptor’s, allowing multiple diverse components to attach at once. This entire structure is called chromatin. As you can imagine visualizing this structure would help tremendously in figuring out how it works. On top of this is epigenetics which is a branch that studies the chemical alteration of histones which in turn affect how DNA is accessed. This is what scientists have figured out. Well just a little.

Scientists at Rice’s Center for Theoretical Biological Physics have used info from a human chromosome to create a 3-D model of it; albeit only during interphase (the cell is just relaxing). It would be best if it could be acquired during the other phases of cellular division since it would help to see how it is processed. This model is called the Minimum Chromatin Model (MiChroM) and was shown to be accurate for the other chromosomes as well. Since we have 23 pairs and each one is different it either has to work for them all or you need a different model for each one. To make things worse each different type of cell has chromosomes that are folded in different ways due to the need to respond to different environments. This creates an intricate system of connections and blockers which requires very close attention to understand.

To place this in perspective genes in your DNA, which are used to make RNA which is used to make proteins which basically do everything in your cells, are less active when they’re wound up tight, blocking direct access. Muscle cells need specific proteins synthesized near continuously. Pancreatic and lung cells have completely different environments they interact with. Cardiac cells need to work in synchrony to ensure the heart is always beating. Neural cells need to maintain specific quantities of ions for electrical activity. The accessibility of the DNA will always be important here so understanding how it works exactly would grant scientific and medical discoveries across all fields.

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