Less than 10% of the human genome contains coded information in the form of genes. The 30,000-40,000 genes in the genome are found grouped in discrete regions of the chromosomes. Chemical agents and radiation habitually cause a large variety of injuries to the DNA which interferes in many cell processes, like transcription and replication, and this can cause a loss of control of cell division and the appearance of tumours. In order to avoid this, the human genome contains more than 130 DNA repair genes which are coded by proteins that constantly scrutinise the genome and seek out damage in order to eliminate it.
A team of researchers from the Mutation Group at the Department of Genetics and Microbiology from the Autonomous University of Barcelona, together with investigators from Leiden University Medical Centre in Leiden (Holland), have discovered that the most important part of the human genome, that is to say the zones where the genes are grouped, are subject to a special and preferential control by the repair mechanisms. In this way, the presence of mutations and the appearance of cancer in the most active genes are prevented.
In order to determine how the repair mechanisms act in the whole human genome, the UAB scientists have studied lines of cells derived from the skin of healthy people and from patients deficient in the repair of DNA damage produced by solar radiation, a genetic disorder called xeroderma pigmentosa. In those affected by this disorder (popularised by the characters of the children in the film The Others), the repair mechanisms do not act when ultraviolet light shines on the skin cells, which causes them to have an accumulation of mutations and, therefore, an extremely high incidence of melanoma (skin cancer). The scientists have been able to observe how the repair of damage caused by ultraviolet rays is concentrated in the richest regions of the genome and, therefore, there is preferential repair of the most important part of the genome, called the transcriptome. By way of example, chromosome 19, the densest and most genetically active, shows high levels of repair, whereas in chromosome 4, one of the poorest in genes, there is practically no preferential repair of the mutations induced by ultraviolet light.
Octavi López Coronado | alfa
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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