Using a novel method, a group of researchers from CSIR-Centre for Cellular and Molecular Biology, Hyderabad (CCMB) and Tata Institute for Genetics and Society, Bengaluru (TIGS), have established a way of studying the nuclear matrix of the fruit fly (Drosophila melanogaster) without removing the nucleus from the embryo.
GS III: Science and Technology
Dimensions of the Article:
- What is Nuclear matrix?
- Different way in which the genome is folded and packaged in different types of cell:
- NuMat preparation
What is Nuclear matrix?
- Every cell that makes up an organism contains a copy of its genome.
- This genome is packaged in special ways with the help of a structure known as the nuclear matrix. The nuclear matrix gives an organisation and architecture to the nucleus.
- The nuclear matrix is like a scaffolding.
- This is a dynamic material providing access for the regulation of different genes in different cells. Studying the nuclear matrix is, therefore, very important to get a better picture of how precisely development progresses every time a new individual is born.
- Using biochemical means, if the nucleus is taken out and treated with an enzyme that digests all the DNA, then washed with a solution of high salt concentration so that viable DNA proteins or protein-protein interactions are removed, what is then left is a fibrous meshwork of proteins called the nuclear matrix.
- This is like a building from which all movables have been sucked out, leaving only the beams, ceiling, walls, plug points, etc.
- Analogous to the building, the nuclear matrix creates the architecture in which the genome is packaged.
Different way in which the genome is folded and packaged in different types of cell:
- We have 220 different types of cells in the body, but all contain identical genomes.
- The same genome sequence is present in neurons, where it works for thinking; in the liver, the same sequence enacts metabolism; and in the intestine, it works to digest. So, this information is packaged differently in different cell types.
- To give an example that justifies the different way in which the genome is folded and packaged in different types of cell, consider proteases.
- These are enzymes that digest proteins and are active in the intestine.
- The intestine contains a lining that prevents these enzymes from digesting the proteins present there, thereby protecting the intestine.
- The same are found in the brain cells also. If they were allowed to be active, they would digest the brain cells which do not have the protective epithelium, and that would be disastrous.
- So, the genome, despite carrying all the genetic material, is packaged such that some genetic material is hidden in such a way that it is never seen by transcription machinery.
- Our body has about 220 different kinds of cells. So, that means the same genome can be packaged in 220 different ways.
- The researchers collect embryos which are between zero and 16 hours old.
- They make, for the first time, the in situ nuclear matrix preparation using this entire collection of embryos. Then, they image them.
- Some are in very early developmental stages, where they are made up of nuclei only, or just making a mono layer of nuclei across the embryos or have gone through differentiation. The array is made available in one preparation.
-Source: The Hindu