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Molecular & Cell Biology

Category: Molecular & Cell Biology


A single thymic epithelial cell (red) in contact with developing T cells (white).
Researchers at the universities of Basel and Oxford have for the first time identified all genes regulated by the protein Foxn1. The results show that Foxn1 not only plays a crucial role in development of the thymus in the embryo, but it also regulates vital functions in the developed, postnatal organ. The decryption of the protein's functions is important in the understanding and treatment of autoimmune diseases, vaccination responses in old age and defense against tumor cells. The study was published in the journal Nature Immunology.


Protective telomeres are augmented by freely diffusing telomerase.
As the rope of a chromosomes replicates, it frays at the ends. No problem: A chromosome's ends have extra twine so that fraying doesn't reach into the body of the rope where the important information resides. This extra twine is called a "telomere". Over time and across replications, this telomere twine breaks down until the chromosome loses its protective ends and this "fraying" reaches into the rope, wrecking the chromosome and resulting in the death of the cell.


Ovarian follicle of fruit fly, with chromosomes stained in green and dKDM5 protein stained in red.
At the start of reproductive life an ovary contains, on average, several thousands of immature ovules in a resting state that can last for several decades. But how does each resting ovule know that it is time to prepare for ovulation? In a study published in the latest issue of Nature Communications*, researchers at Instituto Gulbenkian de Ciencia (IGC; Portugal), at University of Algarve (Portugal), and at University at Albany (USA) discovered in the fruit fly a molecular "alarm clock" that tells resting ovules when is the right time to wake up. Defects in this alarm clock result in female fertility problems.


The fly brain recognizes and processes movements very quickly and accurately.
As indicated by their name, photoreceptor cells in the eye respond to light: is an image point bright or dark? They do not indicate the direction of a movement. This perception only arises in the brain through the comparative computations of light signals coming from adjacent image points. Engineers, physicists and neurobiologists have been debating the exact nature of these computations for around 50 years. Scientists from the Max Planck Institute of Neurobiology have now combined two theories about these computations, which were previously considered to be alternative hypotheses - and discovered that they are carried out in a single neuron.


3-D reconstruction of a GluMI cell at the ultrastructural level showing its input (magenta puncta) and output (yellow puncta) obtained using serial block face scanning electron microscopy.
In the retina of mice, a new type of neuron that falls outside century-old classifications has been discovered.

Duke Health-led researchers have discovered new information about the signaling mechanism of cells that could one day help guide development of more specific drug therapies.

Proteins that bind DNA or RNA are usually put in different categories, but researchers at Umeå University in Sweden and Inserm in France recently showed how the p53 protein has the capacity to bind both and how this controls gene expression on the levels of both transcription (RNA synthesis) and mRNA translation (protein synthesis). The discovery was presented in the July issue of the journal Oncogene.


Authors of the new paper include (left to right) Changchun Xiao, David Nemazee, Alicia Gonzalez Martin and Maoyi Lai of The Scripps Research Institute.
A new study, led by scientists at The Scripps Research Institute (TSRI), reveals a surprising twist in immune biology.


Roundworms (Caenorhabditis elegans) with a disabled eri-1 gene can lose their ability to control repetitive DNA. In the absence of eri-1, even two age-matched siblings can look dramatically different. Cancers arise in skin, muscle, liver or other types of tissue when one cell becomes different from its neighbors. Although biologists have learned a lot about how tissues form during development, very little is known about how two cells of the same tissue stay identical for an animal's entire lifetime.


Atomic force microscopy image of the pore.
The best hiding place often lies behind enemy lines, as many bacteria such as the pathogens responsible for tuberculosis or typhoid have realized. They invade immune cells and can survive there, well hidden, for some time. To eliminate such invaders, the host macrophages can initiate a suicide program. Together with researchers at the Novartis Institute for Biomedical Research and ETH Zurich, the team led by Prof. Sebastian Hiller from the Biozentrum at the University of Basel has shown for the first time that a "death protein" perforates the cell membrane, resulting in macrophage bursting open. The re-exposed pathogens can then again be fought by the immune system.

A powerful new technology that maps the "social network" of proteins in breast cancer cells is providing detailed understanding of the disease at a molecular level and could eventually lead to new treatments, Australian scientists say.

A common feature of cancer and aging is cells' reduced ability to respond to stress-induced damage to DNA or cellular structures. Specifically, changes occur in the protective processes of apoptosis and cellular senescence, whose roles in cancer and aging are thoroughly reviewed by Cerella et al. in Current Drug Targets (Bentham Science Publishers). The authors outline the evidence that these processes are regulated by separate but intertwined pathways. Understanding the precise mechanisms, they conclude, could lead to combination therapies for cancer and aging able to harness the benefits of both apoptosis and senescence, while limiting the drawbacks of either.


Aminopeptidase N is a protein that acts as a receptor for coronaviruses, the family of viruses behind recent epidemics of SARS and MERS, among others.
BETHESDA, MD - The constant battle between pathogens and their hosts has long been recognized as a key driver of evolution, but until now scientists have not had the tools to look at these patterns globally across species and genomes. In a new study, researchers apply big-data analysis to reveal the full extent of viruses' impact on the evolution of humans and other mammals.

Every cancer starts with a single cell, and Jackson Laboratory (JAX) researchers have found a precise and reliable way -- whole-genome profiling of open chromatin -- to identify the kind of cell that leads to a given case of leukemia, a valuable key to cancer prognosis and outcome.


Immunofluorescent breast cancer cells used in this study.
Sometimes, the silencing of a gene is as important as its activation. Nonetheless, up to now, most studies on hormone-mediated gene regulation have focused on researching the factors that influence the activation of certain genes. Little attention has been paid to gene silencing.

Infertility affects about 15 percent of couples around the world. A couple's fertility depends on both the female's and male's ability to reproduce, which relies on thousands of genes working properly. In the male mouse, more than 1,000 genes are predominantly expressed in the testis, but their particular functions in reproduction are still a mystery. In a report published today in the Proceedings of the National Academy of Sciences, researchers from Baylor College of Medicine, Osaka University, University of Oulu and the Wellcome Trust Sanger Institute have discovered that 54 of the mouse testis-enriched genes, that also are expressed in humans, are not necessary for male fertility.

A molecule that enables strong communication between our brain and muscles appears to also aid essential communication between our neurons, scientists report.


When you look very close up at a butterfly wing, you can see this patchwork map of lattices with slightly different orientations (colors added to illustrate the domains).
Scientists used X-rays to discover what creates one butterfly effect: how the microscopic structures on the insect's wings reflect light to appear as brilliant colors to the eye.


A bacterial colony showing individual cells undergoing transposable element events, resulting in blue fluorescence.
"Jumping genes" are ubiquitous. Every domain of life hosts these sequences of DNA that can "jump" from one position to another along a chromosome; in fact, nearly half the human genome is made up of jumping genes. Depending on their specific excision and insertion points, jumping genes can interrupt or trigger gene expression, driving genetic mutation and contributing to cell diversification. Since their discovery in the 1940s, researchers have been able to study the behavior of these jumping genes, generally known as transposons or transposable elements (TE), primarily through indirect methods that infer individual activity from bulk results. However, such techniques are not sensitive enough to determine precisely how or why the transposons jump, and what factors trigger their activity.

Biologically speaking, we carry the outside world within us. The food we ingest each day and the trillions of microbes that inhabit our guts pose a constant risk of infection--and all that separates us from these foreign entities is a delicate boundary made of a single layer of cells.

Northwestern Medicine and University of Wisconsin-Madison (UW) scientists have identified a gene that causes severe glaucoma in children. The finding, published in The Journal of Clinical Investigation, validates a similar discovery made by the scientists in mice two years ago and suggests a target for future therapies to treat the devastating eye disease that currently has no cure.


Johan Flygare and Sandra Capellera.
Eight days. That's how long it takes for skin cells to reprogram into red blood cells. Researchers at Lund University in Sweden, together with colleagues at Center of Regenerative Medicine in Barcelona, have successfully identified the four genetic keys that unlock the genetic code of skin cells and reprogram them to start producing red blood cells instead.

For a long time dismissed as "junk DNA", we now know that also the regions between the genes fulfil vital functions. Mutations in those DNA regions can severely impair development in humans and may lead to serious diseases later in life. Until now, however, regulatory DNA regions have been hard to find. Scientists around Prof. Julien Gagneur, Professor for Computational Biology at the Technical University of Munich (TUM) and Prof. Patrick Cramer at the Max Planck Institute (MPI) for Biophysical Chemistry in Göttingen have now developed a method to find regulatory DNA regions which are active and controlling genes.

New identification of a gene involved in the fracture healing process could lead to the development of new therapeutic treatments for difficult-to-heal injuries.

New research by Steven Laviolette's research team at Western University is contributing to a better understanding of the ways opiate-class drugs modify brain circuits to drive the addiction cycle. Using rodent models of opiate addiction, Dr. Laviolette's research has shown that opiates affect pathways of associative memory formation in multiple ways, both at the level of anatomy (connections between neurons) and at the molecular levels (how molecules inside the brain affect these connections). The identification of these opiate-induced changes offers the best hope for developing more effective pharmacological targets and therapies to prevent or reverse the effect of opiate exposure and addiction. These results were presented at the 10th Annual Canadian Neuroscience Meeting, taking place May 29 to June 1 2016, in Toronto, Canada.

Scientists at the University of Birmingham are a step closer to understanding the role of the gene BRCA1. Changes in this gene are associated with a high risk of developing breast and ovarian cancer.

Just as members of an orchestra need a conductor to stay on tempo, neurons in the brain need well-timed waves of activity to organize memories across time. In the hippocampus--the brain's memory center--temporal ordering of the neural code is important for building a mental map of where you've been, where you are, and where you are going. Published on May 30 in Nature Neuroscience, research from the RIKEN Brain Science Institute in Japan has pinpointed how the neurons that represent space in mice stay in time.


Tailor-made ratiometric sensors make baker's yeast cells light up green, as Georgia Tech scientists use it to track the movements of the essential toxin heme.
A pinch of poison is good for a body, at least if it's heme.


Stylized graphic of SEC-SAXS data (with cyan cross-section showing the elution profile and magenta cross-section showing scattering profile) and the structure of the activated phenylalanine hydroxylase
Using a powerful combination of techniques from biophysics to mathematics, researchers have revealed new insights into the mechanism of a liver enzyme that is critical for human health. The enzyme, phenylalanine hydroxylase, turns the essential amino acid phenylalanine -- found in eggs, beef and many other foods and as an additive in diet soda -- into tyrosine, a precursor for multiple important neurotransmitters.

A new study from MIT neuroscientists reveals that a gene mutation associated with autism plays a critical role in the formation and maturation of synapses -- the connections that allow neurons to communicate with each other.

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