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Molecular & Cell Biology

Category: Molecular & Cell Biology

A particular location in DNA, called the Dlk1-Gtl2 locus, plays a critical role in protecting hematopoietic, or blood-forming, stem cells--a discovery revealing a critical role of metabolic control in adult stem cells, and providing insight for potentially diagnosing and treating cancer, according to researchers from the Stowers Institute for Medical Research.

Tufts biologists induced one species of flatworm -- G. dorotocephala, top left -- to grow heads and brains characteristic of other species of flatworm, top row, without altering genomic sequence.
MEDFORD/SOMERVILLE, Mass. (November 24, 2015)--Biologists at Tufts University have succeeded in inducing one species of flatworm to grow heads and brains characteristic of another species of flatworm without altering genomic sequence. The work reveals physiological circuits as a new kind of epigenetics - information existing outside of genomic sequence - that determines large-scale anatomy.

Location of topologically associated domains (TAD) in the cell nucleus is shown.
Chromosome is a structure inside the cell nucleus that carries a large part of the genetic information and is responsible for its storage, transfer and implementation. Chromosome is formed from a very long DNA molecule - a double chain of a plurality of genes. Given that the diameter of the cell nucleus is usually around hundredth of a millimeter or even less, while the total length of DNA constituting human genome is about two meters, it is clear that DNA must be packaged very tightly.

Scientists at the Institute of Molecular Biology (IMB) in Mainz have unraveled a complex regulatory mechanism that explains how a single gene can drive the formation of brain cells. The research, published in The EMBO Journal, is an important step towards a better understanding of how the brain develops. It also harbors potential for regenerative medicine.

Proteins inside bacteria cells engage in "search-and-rescue"-type behavior to ferret out mismatched DNA and fix it to thwart dangerous mutations that can be associated with certain cancers, a University of Michigan study found.

Scientists at the Institute of Molecular Biology (IMB) have been able to see, for the first time, the dramatic changes that occur in the DNA of cells that are starved of oxygen and nutrients. This starved state is typical in some of today's most common diseases, particularly heart attacks, stroke and cancer. The findings provide new insight into the damage these diseases cause and may help researchers to discover new ways of treating them.

The size of returning Atlantic salmon is largely dependent on the number of years that the salmon remains at sea before returning to spawn in the river. The genetic basis of this trait has not been previously known, making the management of the impact of fishing difficult. In many Atlantic salmon populations, the sea-age at maturity, i.e. the number of years at sea, has been declining.

A new discovery published in the Nov. 2015 issue of The FASEB Journal shows that cancer cells use previously unknown channels to communicate with one another and with adjacent non-cancerous cells. Not only does this cast an important light on how cancer metastasizes and recruits cellular material from healthy cells, but it also suggests that these physical channels might be exploitable to deliver drug therapies.

The new type of DNA repair enzyme, AlkD on the left, can identify and remove a damaged DNA base without forcing it to physically "flip" to the outside of the DNA backbone, which is how all the other DNA repair enzymes in its family work, as illustrated by the human AAG enzyme on the right. The enzymes are shown in grey, the DNA backbone is orange, normal DNA base pairs are yellow, the damaged base is blue and its pair base is green.
This year's Nobel Prize in chemistry was given to three scientists who each focused on one piece of the DNA repair puzzle. Now a new study, reported online Oct. 28 in the journal Nature, reports the discovery of a new class of DNA repair enzyme.

Motor proteins that pause at the ends of microtubules and produce pushing forces can also stimulate their growth, according to researchers at Penn State. The proteins' function could be a critical component in understanding cell division and nerve branching and growth.

Basic research into the mechanisms of cell division, using eggs and embryos from frogs and starfish, has led researchers to an unexpected discovery about how animal cells control the forces that shape themselves.

New research has shed light on the molecular changes that occur in our bodies as we age.

Alessandra Angelucci (right), a University of Utah professor of ophthalmology and visual science, and University of Utah computer science professor Valerio Pascucci stand in front of a computer model
The animal brain is so complex, it would take a supercomputer and vast amounts of data to create a detailed 3-D model of the billions of neurons that power it.

Using a sensitive new technology called single-cell RNA-seq on cells from mice, scientists have created the first high-resolution gene expression map of the newborn mouse inner ear. The findings provide new insight into how epithelial cells in the inner ear develop and differentiate into specialized cells that serve critical functions for hearing and maintaining balance. Understanding how these important cells form may provide a foundation for the potential development of cell-based therapies for treating hearing loss and balance disorders. The research was conducted by scientists at the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health.

Johannes Reiter, former PhD student in the group of Krishnendu Chatterjee at the Institute of Science and Technology Austria (IST Austria), is co-author of a Nature paper on genetic alterations that drive the progression and relapse of cancer. An international team of scientists from the US, Germany and Austria identified novel genes associated with chronic lymphocytic leukemia through the analysis of high-throughput sequencing data.

Using a multidisciplinary approach, researchers, led by those at Baylor College of Medicine, revealed in unprecedented detail the three-dimensional structure of biologically active DNA. A report on their work appears online in the journal Nature Communications.

Scientists engineered stem cells to better understand the mechanisms behind a form of leukemia caused by changes in a key gene, according to a study led by Mount Sinai researchers and published online today in the journal Cell Reports.

Cells of multicellular organisms contain identical genetic material (the genome) yet can have drastic differences in their structural arrangements and functions. This variation of the distinct cell types comes from the differential expression of genes, which is controlled by interplay between different regulators within the cells, such as transcription factors, the transcription machinery, and the "epigenetic" modifications (which do not change the underlying genetic code) that occur on the DNA and protein factors within chromatin.

New findings revealed a molecular "tug of war " that plays a key role in the proper functioning of the telomerase enzyme.
Researchers at UC Santa Cruz have determined the structure of a key part of the enzyme telomerase, which is active in most cancers and enables cancer cells to proliferate indefinitely. The new findings, published October 5 in Nature Structural & Molecular Biology, reveal how the enzyme carries out a crucial function involved in protecting the ends of chromosomes.

A single neuron in a normal adult brain likely has more than a thousand genetic mutations that are not present in the cells that surround it, according to new research from Howard Hughes Medical Institute (HHMI) scientists. The majority of these mutations appear to arise while genes are in active use, after brain development is complete.

A group of researchers, led by Prof. MATOZAKI Takashi and Associate Prof. MURATA Yoji at the Kobe University Graduate School of Medicine Division of Molecular and Cellular Signaling, were the first to demonstrate the role of stomach cancer-associated protein tyrosine phosphatase (SAP)-1 in the pathogenesis and prevention of Crohn's disease, ulcerative colitis, and other inflammatory bowel disorders. Their findings, published online ahead of print on July 20, 2015, by the Proceedings of the National Academy of Sciences of the United States of America, are expected to accelerate the development of targeted therapies for inflammatory gastrointestinal diseases.

Salk scientists have developed a new way to selectively activate brain, heart, muscle and other cells using ultrasonic waves. The new technique, dubbed sonogenetics, has some similarities to the burgeoning use of light to activate cells in order to better understand the brain.

Most people are familiar with the double-helix shape that allows genetic information to be packed into a molecule of human DNA. Less well-known is how all this information - which, if laid end-to-end, would stretch some three meters - is packed into the cellular nucleus. The secret of how this crush of genetic code avoids chaos - remaining untangled, correctly compartmentalized, and available for accurate DNA replication - has recently been revealed.

Inside the trillions of cells that make up the human body, things are rarely silent. Molecules are constantly being made, moved, and modified--and during these processes, mistakes are sometimes made. Strands of DNA, for instance, can break for any number of reasons, such as exposure to UV radiation, or mechanical stress on the chromosomes into which our genetic material is packaged.

Scientists have uncovered tens of thousands of new protein interactions, accounting for about a quarter of all estimated protein contacts in a cell.
A multinational team of scientists have sifted through cells of vastly different organisms, from amoebae to worms to mice to humans, to reveal how proteins fit together to build different cells and bodies.

This is a representation of the fluoride ion channel (center) with monobodies attached (top and bottom).
Although present almost everywhere - food, soil, toothpaste and especially tap water -, the fluoride ion is highly toxic to microorganisms and cells. To avoid death, cells must remove fluoride that has accumulated inside them, a process accomplished via ion channels - protein tunnels through the cell membrane that only allow specific substances to pass through.

In the breast, cancer stem cells and normal stem cells can arise from different cell types but tap into distinct yet related stem cell programs, according to Whitehead Institute researchers. The differences between these stem cell programs may be significant enough to be exploited by future therapeutics.

Altering the protein recycling complexes in human cells, including cancer cells, allows the cells to resist treatment with a class of drugs known as proteasome inhibitors, according to Whitehead Institute scientists.

Eliminating HK2 (shown here), which is a key enzyme for glucose metabolism, may be a way to prevent cancer cells from surviving,
A study published in The Journal of Cell Biology describes a way to force cancer cells to destroy a key metabolic enzyme they need to survive.

Olfactory signatures corresponding to specific odorants. In the background, an olfactory sensory neuroepithelium.
In animals, numerous behaviors are governed by the olfactory perception of their surrounding world. Whether originating in the nose of a mammal or the antennas of an insect, perception results from the combined activation of multiple receptors located in these organs. Identifying the full repertoire of receptors stimulated by a given odorant would represent a key step in deciphering the code that mediates these behaviors. To this end, a tool that provides a complete olfactory receptor signature corresponding to any specific smell was developed in the Faculties of Science and Medicine of the University of Geneva (UNIGE), Switzerland. Published in the journal Nature Neuroscience, this approach allows to identify thousands of chemosensory receptors, among which, potentially, those able to trigger predetermined behaviors in mammals or in insects, such as pests, disease vectors or parasites.

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