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Biologists Find Day and Night Pathways Regulating Plant Growth Vigor

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Photo: Hybrid plants (middle two) grow larger and more vigorously than the parents (left and right).

Scientists are slowly unravelling the complex molecular pathways that regulate growth vigor in plant hybrids, with the goal of eventually developing hybrid crops that can grow faster and more productively, while at the same time doing a better job of resisting stress such as heat, drought and pests. Many crops such as corn are grown as hybrids for better yield and traits.

In a new study out this week in the journal Proceedings of the National Academy of Sciences, researchers from The University of Texas at Austin and Peking University identified two new pathways that influence plant growth in hybrids of Arabidopsis, a weedy plant in the mustard family. One pathway works in the daytime via compounds in the circadian clock, a central regulator for plant growth; the other works at night via compounds called phytochrome interacting factors.

These two pathways work by turning up or down a hybrid plant’s production of ethylene, a hormone which inhibits vegetative growth. Because these pathways exist in all plants including most commercially important crops—such as corn, cotton, lettuce and tomatoes—altering ethylene production in these crops might boost yield too.

This project was a collaboration between four different research groups, headed by the D. J. Sibley Centennial Professor Z. Jeffrey Chen, assistant professor Hong Qiao, and professor Enamul Huq, all three in the Department of Molecular Biosciences at UT Austin; and Xing Wang Deng, professor and Dean of the School of Advanced Agriculture Sciences and School of Life Sciences at Peking University.

Chen said there are several ways the new findings of regulating plant growth vigor might be used to boost crop yields: plant breeders could do genetic tests to identify parent plants for cross breeding that reduce ethylene production; biotech companies could genetically engineer crops with lower ethylene production; or farmers could apply chemicals that inhibit ethylene production in crops growing in the field.

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Photo credit: Alberto Salguero Quiles. Image used under a Creative Commons license (CC BY-SA 3.0).

Study of Immune Protein Could Help Fight Tuberculosis, Other Pathogens

Scientists at UT Austin have revealed how a protein called ISG15 helps the human immune system fight certain pathogens, including the microbe that causes tuberculosis. In 2012, the group was part of a study that demonstrated that ISG15 stimulates the release of a cytokine, Interferon-g, important in the response to pathogenic bacteria. With this latest work, published this week in the journal Molecular Cell, these scientists have identified the cell surface receptor for ISG15 and determined the initial steps in how it activates the secretion of a range of cytokines.

Jon Huibregtse, UT Austin professor of molecular biosciences who led the study, said this may provide new insights into how to modulate immune responses and treat microbial infections.

“We think we may be on the trail of an entirely new mechanism for stimulating cytokine secretion,” said Huibregtse, “and that this might have implications for a wide variety of infectious diseases.”

Read the paper: Extracellular ISG15 Signals Cytokine Secretion through the LFA-1 Integrin Receptor

New MBS Faculty Member Receives Etter Early Career Award

mclellanJason McLellan, future associate professor in the Department of Molecular Biosciences, has received the Etter Early Career Award from the American Crystallographic Association.

The Etter Early Career award, which was established in 2002, seeks to recognize outstanding achievement and exceptional potential in crystallographic research demonstrated by a scientist at an early stage of their independent career.

McLellan’s research focuses on applying structural information to the rational design of interventions for viruses, specifically the respiratory syncytial virus (RSV). According to the Centers for Disease Control and Prevention, nearly every child in the US catches RSV, a virus that infects the lungs and respiratory tract, by the age of two.

He has been working to develop a monoclonal antibody, a type of antibody that targets only one specific protein, which could act as a vaccine surrogate to prevent severe RSV in infants.

McLellan, who is currently an assistant professor at Dartmouth College, will join the UT Austin faculty in January 2018.

Jonghwan Kim Receives Grant to Study Preterm Births

The Burroughs Wellcome Fund has awarded Jonghwan Kim, an assistant professor in the Department of Molecular Biosciences at The University of Texas at Austin, a four-year, $600,000 grant to study the biological complexities of preterm birth.

Surprisingly, little is known about the biological mechanisms that occur during birth.  Even less is known about what causes preterm birth.  Defined as babies born before 37 weeks, preterm birth occurs in nearly 13 percent of all U.S births, with African-Americans and Hispanics having an even higher rate.

Preterm Birth is a major public health problem. Many preterm births lead to long-term health problems and developmental difficulties. There are also the sociological issues of families going bankrupt and marriages dissolving.

Kim’s research project is titled “Identifying genetic factors controlling normal and abnormal placental development.”

Burroughs Wellcome Fund’s ultimate goal is to help develop preventive strategies by enabling interdisciplinary teams to collaborate in learning more about preterm birth.

Steven Vokes Receives Grant for Cancer Research

090121 VokesThe St. Baldrick’s Foundation has awarded a $100,000 grant to Associate Professor Steven Vokes for his research to identify cures and better treatments for childhood cancers.

Medulloblastoma, the most common brain cancer in children, is formed by mutations that active a signaling pathway. With his grant from St. Baldrick’s, Dr. Vokes and his team are investigating how this pathway controls genes through specific DNA regions. By studying these regions, they hope to find a possible therapeutic target for medulloblastoma. 

"One of the challenges in today's highly competitive environment is that even great ideas take a long time to get funded. St. Baldrick's has a streamlined review process that quickly funds promising research. Their support has allowed us to quickly initiate experiments in a promising new area that we would otherwise be unable to pursue,” Vokes said.

St. Baldrick’s, a California-based nonprofit, is the largest private funder of childhood cancer research grants. The nonprofit recently awarded 79 grants totaling over $22 million. St. Baldrick's funds are granted to some of the top childhood cancer research experts working to find improved treatments and cures for childhood cancers. 

Discovery Sheds New Light on RNA Regulation

Scientists at the University of Texas at Austin have disproven a decades-old assumption about the molecular machinery responsible for producing proteins in all living things. The discovery could force researchers to rethink how they interpret results of experiments related to this machinery.

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Floating in every cell in your body are molecules of RNA, which act as templates for all the different flavors of protein that are essential for life. Often, an RNA molecule contains within itself elements that control if and when to make protein. Other elements can help guide the RNA to the right places inside the cell. The assumption, going right back to the earliest studies of gene regulation, was that control elements embedded in one RNA only affect what happens to that RNA.

Paul Macdonald, a professor of molecular biosciences, and his team discovered that a control element in one RNA can affect the production of proteins from other RNAs. Control elements can even affect production of proteins from completely different types of RNAs. They made the discovery by studying the developing embryos of fruit flies.

For researchers trying to understand what individual genes do and how they get translated into proteins, this poses a problem. A typical approach involves "knocking out" a gene, by genetically engineering mutations in it's associated RNA, to see what biological processes break down. Macdonald's finding suggests that removing one RNA could potentially affect the expression of other RNAs.

The findings were published online in the open access journal eLife on April 22.

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