cryptochrome
Credit: Pixabay/CC0 Public Domain

Scientists from the University of Seville, in collaboration with colleagues from the Universities of Marburg (Germany) & Murcia, have identified a novel protein that — makes it possible to repair Deoxyribonucleic acid (DNA). The protein in question, known as — cryptochrome, has evolved to acquire this & other functions within the cell.

The results have been published in an article in Current Biology.

UV radiation can damage the DNA, leading to mutations that — disrupt cell function & can allow cancer cells to grow out of control. Our cells have DNA repair systems to defend themselves against this sort of damage. One of these systems is based on a protein, UV radiation can damage the DNA, leading to mutations that disrupt cell function and can allow cancer cells to grow out of control. Our cells have DNA repair systems to defend themselves against this sort of damage. 1 of these systems is based on a protein, photolysis which uses — blue light to repair DNA damage before it leads to mutations. which uses blue light to repair DNA damage before it leads to mutations.

Over the course of evolution, the genes for photolysis duplicated and became specialized, creating new proteins, cryptochromes, which have honed their ability to perceive blue light & now perform other functions in cells. such as, cryptochromes use blue light as a signal to regulate plant growth and the rhythm that controls daily activity (the circadian rhythm) in fungi and animals.

The authors of this study discovered that in the fungus Mucor circinelloides, a human pathogen, cryptochromes are the protein responsible for DNA repair after exposure to UV radiation, a function that should be performed by photolysis. They also suggest that cryptochromes in this fungus acquired their ability to repair DNA during evolution from an ancestral cryptochrome that was not able to repair DNA. This discovery illustrates how proteins change as their functions evolve.

More information: Eusebio Navarro et al. The DASH-type Cryptochrome from the Fungus Mucor circinelloides Is a Canonical CPD-Photolyase, Current Biology (2020). DOI: 10.1016/j.cub.2020.08.051