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Category: genetics

Constructing gene circuits that satisfy quantitative performance criteria has been a long‐standing challenge in synthetic biology. Here, we show a strategy for optimizing a complex three‐gene circuit, a novel proportional miRNA biosensor, using predictive modeling to initiate a search in the phase space of sensor genetic composition. We generate a library of sensor circuits using diverse genetic building blocks in order to access favorable parameter combinations and uncover specific genetic compositions with greatly improved dynamic range. The combination of high‐throughput screening data and the data obtained from detailed mechanistic interrogation of a small number of sensors was used to validate the model. The validated model facilitated further experimentation, including biosensor reprogramming and biosensor integration into larger networks, enabling in principle arbitrary logic with miRNA inputs using normal form circuits. The study reveals how model‐guided generation of genetic diversity followed by screening and model validation can be successfully applied to optimize performance of complex gene networks without extensive prior knowledge.

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Well before the family came in to the Batson Children’s Specialty Clinic in Jackson, Mississippi, they knew something was wrong. Their child was born with multiple birth defects, and didn’t look like any of its kin. A couple of tests for genetic syndromes came back negative, but Omar Abdul-Rahman, Chief of Medical Genetics at the University of Mississippi, had a strong hunch that the child had Mowat-Wilson syndrome, a rare disease associated with challenging life-long symptoms like speech impediments and seizures.

So he pulled out one of his most prized physicians’ tools: his cell phone.

Using an app called Face2Gene, Abdul-Rahman snapped a quick photo of the child’s face. Within a matter of seconds, the app generated a list of potential diagnoses — and corroborated his hunch. “Sure enough, Mowat-Wilson syndrome came up on the list,” Abdul-Rahman recalls.

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The gene drive is quickly becoming one of the most controversial technologies of our time. Its possibilities are at once spectacular and alarming: by using genetic engineering to override natural selection during reproduction, a gene drive could allow scientists to alter the genetic makeup of an entire species. This could be used to eliminate diseases and protect natural habitats —but could also go horribly wrong in the wrong hands.

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Excellent read on the brain’s inhibitory circuits v. excitatory circuits when involving the processing of smells.

Summary: Inhibitory neurons form neural networks that become broader as they mature, a new study reports.

Source: Baylor College of Medicine.

Scientists have discovered that networks of inhibitory brain cells or neurons develop through a mechanism opposite to the one followed by excitatory networks. Excitatory neurons sculpt and refine maps of the external world throughout development and experience, while inhibitory neurons form maps that become broader with maturation. This discovery adds a new piece to the puzzle of how the brain organizes and processes information. Knowing how the normal brain works is an important step toward understanding the nature of neurological conditions and opens the possibility of finding treatments in the future. The results appear in Nature Neuroscience.

“The brain represents the external world as specific maps of activity created by networks of neurons,” said senior author Dr. Benjamin Arenkiel, associate professor of molecular and human genetics and of neuroscience at Baylor College of Medicine, who studies neural maps in the olfactory system of the laboratory mouse. “Most of these maps have been studied in the excitatory circuits of the brain because excitatory neurons in the cortex outnumber inhibitory neurons.”

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What humans will look like in 100 years: Expert reveals the genetically modified bodies we’ll need to survive

  • Harvard researchers says to survive the next extinction we must leave the Earth
  • But to live on other planets we will need to genetically modify our organs
  • Experts have previously speculated how humanity will look in 1,000 years’ time
  • Video describes scenario in which bodies are part-human part-machine

By Harry Pettit For Mailonline

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Of all the potentially apocalyptic technologies scientists have come up with in recent years, the gene drive is easily one of the most terrifying. A gene drive is a tool that allows scientists to use genetic engineering to override natural selection during reproduction. In theory, scientists could use it to alter the genetic makeup of an entire species—or even wipe that species out. It’s not hard to imagine how a slip-up in the lab could lead to things going very, very wrong.

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It may be possible to reduce, stop or even prevent absence seizures, the most common form of childhood epilepsy, according to a study published in the leading scientific journal Neuron.

Using an advanced technology called optogenetics and a rodent model, researchers at Stanford University School of Medicine showed that it is possible to trigger seizures by inducing synchronized, rhythmic activity within a particular structure in the brain called the thalamocortical tract. Importantly, they also demonstrated that disrupting this activity is sufficient to terminate the seizures.

For the study the team, led by Dr Jeanne Paz, inserted a gene that encodes for a light-sensitive cell-surface protein into a set of nerve cells situated in the thalamocortical tract of rat and mice models of absence seizures. This way, the scientists were able to prevent these cells from firing by shining a yellow light onto them.

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A new genetic disease has been discovered that could play a key role in devastating brain conditions such as Alzheimer’s and Parkinson’s, opening up the possibility of new forms of treatment.

A 47-year-old Canadian woman, who had been having difficulty walking and balancing since she was 28, was found to have a new genetic disease after 10 known conditions were ruled out, according to a paper in the journal Nature by an international team of researchers.

The disease causes an over-reaction by the body’s natural repair system. An enzyme, known as PARP1, goes into over-drive, ultimately causing the deaths of brain cells.

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New study provides deeper insight into the immune system.

In a bid to better understand the gene expression patterns that control T cell activity, researchers at the La Jolla Institute for Allergy and Immunology mapped genome-wide changes in chromatin accessibility as T cells respond to acute and chronic virus infections. Their findings, published in the Dec. 20, 2016 issue of Immunity, shed light on the molecular mechanisms that determine the fate of T lymphocytes and open new approaches to clinical intervention strategies to modulate T cell activity and improve immune function.

“Identifying the different factors that determine different T cell states and therefore their function helps us understand if T cells will be able or not to fight viral infections or tumor growth, and if they will be able or not to provide long-term protection,” says the study’s first author James Scott-Browne, a postdoctoral fellow in the laboratory of Anjana Rao, a professor in the Division of Signaling and Gene Expression. “We may be able to revert the exhaustion phenotype of T cells and render them better able to fight tumors or chronic viral infections such as HIV, or generate better memory cells in response to vaccines.”

When viruses invade or cells turn malignant, the immune system mobilizes a small cohort of naïve or immature CD8 T cells, a crucial subdivision of the immune system charged with killing virus-infected and . Upon activation, they mature and proliferate exponentially into highly specific effector T cells that eliminate virus-infected or otherwise compromised cells. After their job is done, most effector T cells die leaving behind only a small contingent of memory T cell that confer long-term protection.

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