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Can we dwell longer? Physicists do analysis on telomeres

Determine 1: Cell, chromosome and telomere. Credit score: Fiennes Lieflong/Leiden College

With the assistance of physics and a minuscule magnet, researchers have found a brand new construction of telomeric DNA. Telomeres are generally seen as the important thing to longevity. They defend genes from injury however get somewhat smaller every time the cell divides. If they’re too small, the cell dies. New discovery helps us perceive getting old and illness.

Physics just isn’t the primary scientific self-discipline that involves thoughts on the point out of DNA. However Jan van Noort of the Leiden Institute of Physics (LION) was one of many scientists who found the brand new DNA construction. A biophysicist, he makes use of physics strategies for organic experiments. It additionally caught the eye of biologists at Singapore’s Nanyang Technological College. He requested him to assist research the DNA construction of telomeres. They’ve revealed the outcomes the character.

A string of beads

Each cell in our physique incorporates chromosomes that include genes that decide our traits (for instance, how we glance). On the ends of those chromosomes are telomeres, which defend the chromosomes from injury. They’re somewhat like auglets, the plastic ends on the finish of a shoelace.

The DNA between telomeres is 2 meters lengthy, so it must be folded to slot in the cell. That is achieved by wrapping DNA round packages of proteins; Collectively, DNA and proteins are referred to as nucleosomes. These are connected to a nucleosome, a free (or unbound) piece of DNA, much like a string of beads with a nucleosome and so forth.

Can we live longer?  Leiden physicist makes discovery in protective layer in genes

Determine 2: Three completely different DNA constructions. Credit score: Fiennes Lieflong/Leiden College

This string of beads is then folded additional. How that will depend on the size of DNA between nucleosomes, the beads on the string. Two constructions that happen after folding have been already recognized. In one among them, two adjoining beads stick collectively and free DNA hangs between them (Fig. 2A). If the piece of DNA between the beads is brief, adjoining beads won’t stick collectively. Two piles are then shaped subsequent to one another (Fig. 2B).

Of their research, van Noort and colleagues discovered one other telomere construction. Right here the nucleosomes are a lot nearer collectively, so there is no such thing as a free DNA between the beads. This finally creates a big helix or coil of DNA (Fig. 2C).

The brand new construction was found with a mixture of electron microscopy and molecular pressure spectroscopy. The latter approach comes from Van Noort’s laboratory. Right here one finish of the DNA is connected to a glass slide and the opposite is connected to a small magnetic ball. A set of robust magnets on high of this ball then pulls the string of pearls. By measuring the quantity of pressure required to tug the beads one after the other, you study extra about how the string is folded. The Singaporean researchers then used electron microscopy to get a greater image of the construction.

The construction, says van Noort, is “the holy grail of molecular biology.” If we all know the construction of molecules, it provides us extra perception into how genes are turned on and off, and the way enzymes in cells cope with telomeres: how they restore and replica DNA, for instance. The invention of a brand new telomeric construction improves our understanding of the constructing blocks within the physique. And that may in the end assist us research illnesses like getting old and most cancers and develop medicine to combat them.


DNA bending prices much less power than assumed


Extra data:
Aghil Soman et al., Columnar construction of human telomeric chromatin, the character (2022) DOI: 10.1038/s41586-022-05236-5

Supplied by Leiden College

reference: Can we dwell longer? Physicist Discovering Telomeres (2022, September 15) Retrieved 15 September 2022 from https://phys.org/information/2022-09-longer-physicist-discovery-telomeres.html

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