The thyroid gland secretes thyroxine (TH), a hormone essential for the growth and development of all vertebrates including humans. To understand TH action, the Donald Brown lab studies one of the most dramatic roles of the hormone, the control of amphibian metamorphosis—the process by which a tadpole turns into a frog. He studies the frog Xenopus laevis, from South Africa, because it is easy to rear. Events as different as the formation of limbs, the remodeling of organs, and the resorption of tadpole tissues such as the tail are all directed by TH. How can a simple molecule control so many different developmental changes? The hormone works by regulating the expression of groups of genes. It instructs some genes to absorb the tail and gills and others to start new tissues and organs.

The lab has developed a strategy to analyze this complex programing. They have identified genes that are regulated by TH in a variety of tissues and organs by hybridizing probes with micro arrays prepared by Agilent Technologies.

Scientific Area: 
Genetics & Developmental Biology
Reference to Person: 
Donald Brown

Explore Carnegie Science

How Invading Jumping Genes are Thwarted
November 1, 2018

Baltimore, MD—Since Carnegie Institution’s Barbara McClintock received her Nobel Prize on her discovery of jumping genes in 1983, we have learned that almost half of our DNA is made up of jumping genes—called transposons. Given their ability of jumping around the genome in developing sperm and egg cells, their invasion triggers DNA damage and mutations. This often leads to animal sterility or even death, threatening species survival. The high abundance of jumping genes implies that organisms have survived millions, if not billions, of transposon invasions. However, little is known about where this adaptability comes from. Now, a team of Carnegie researchers has discovered that, upon

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Steven Farber Awarded $3.3-Million NIH Grant To Identify New Pharmaceuticals To Fight Cardiovascular Disease
October 10, 2018

Carnegie’s Department of Embryology scientist Steven Farber and team have been awarded a 5-year $3.3-million NIH grant to identify novel pharmaceuticals for combating a host of diseases associated with altered levels of lipoproteins like LDL (“bad cholesterol”). Obesity, diabetes, cardiovascular disease, fatty liver disease, and metabolic syndrome have all been linked to changes in plasma lipoproteins. 

Lab efforts, led by graduate student Jay Thierer, started by creating zebrafish that have been genetically engineered to produce glowing lipoproteins, a technique they call “LipoGlo”. This was achieved by attaching DNA encoding NanoLuc (a relative of the protein that makes

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Former Carnegie Postdoctoral Fellow Tasuku Honjo Shares Nobel Prize
October 1, 2018

Tasuku Honjo, a postdoctoral fellow in the Brown Lab at the Department of Embryology 1971-1973, shares the 2018 Nobel Prize in Physiology or Medicine.

The AsianScientist quoted Honjo as saying: "After I moved to the US as a postdoctoral researcher in the 70s, I met my mentor, Dr. Donald Brown, at the Carnegie Institution for Science in Baltimore. He told me that the major question of immunology at the time was, how do we create such an enormous diversity of antibodies? That question is now ready to be tackled using a molecular strategy." Read the official Nobel press release. Image courtesy Nobel.org

 

 

 
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Intestines modify their cellular structure in response to diet
September 20, 2018

Baltimore, MD— Body organs such as the intestine and ovaries undergo structural changes in response to dietary nutrients that can have lasting impacts on metabolism, as well as cancer susceptibility, according to Carnegie’s Rebecca Obniski, Matthew Sieber, and Allan Spradling.

Their work, published by Developmental Cell, used fruit flies, which are currently the most-sensitive experimental system for such detecting diet-induced cellular changes that are likely to be similar in mammals.

There are three major types of cells in fruit fly (and mammalian) intestines: Stem cells, hormone-producing cells, and nutrient-handling cells. Think of the stem cells as blanks, which are

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Mechanisms of cell division, homeostasis, aging, and cell fate

The Zheng lab studies cell division including the study of stem cells, genome organization, and lineage specification. They study the mechanism of genome organization in development, homeostasis—metabolic balance-- and aging; and the influence of cell morphogenesis, or cell shape and steructure,  on cell fate decisions. They use a wide range of tools and systems, including genetics in model organisms, cell culture, biochemistry, proteomics, and genomics.

 
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The biology of reproduction studying ovarian stem cells of the fruitfly

The Spradling laboratory studies the biology of reproduction. By unknown means eggs reset the normally irreversible processes of differentiation and aging. The fruit fly Drosophila provides a favorable multicellular system for molecular genetic studies. The lab focuses on several aspects of egg development, called oogenesis, which promises to provide insight into the rejuvenation of the nucleus and surrounding cytoplasm. By studying ovarian stem cells, they are learning how cells maintain an undifferentiated state and how cell production is regulated by microenvironments known as niches. They are  also re-investigating the role of steroid and prostaglandin hormones in controlling the

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The mechanics of stem cell development

Stem cells make headline news as potential treatments for a variety of diseases. But undertstanding the nuts and bolts of how they develop from an undifferentiated cell  that gives rise to cells that are specialized such as organs, or bones, and the nervous system, is not well understood. 

The Lepper lab studies the mechanics of these processes. overturned previous research that identified critical genes for making muscle stem cells. It turns out that the genes that make muscle stem cells in the embryo are surprisingly not needed in adult muscle stem cells to regenerate muscles after injury. The finding challenges the current course of research into muscular dystrophy, muscle

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Left and right side differences of the developing brain

The Marnie Halpern laboratory studies how left-right differences arise in the developing brain and discovers the genes that control this asymmetry. Using the tiny zebrafish, Danio rerio, they explores how regional specializations occur within the neural tube, the embryonic tissue that develops into the brain and spinal cord.

The zebrafish is ideal for these studies because its basic body plan is set within 24 hours of fertilization. By day five, young larvae are able to feed and swim, and within three months they are ready to reproduce. They are also prolific breeders. Most importantly the embryos are transparent, allowing scientists to watch the nervous system develop and to

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William Ludington

The Ludington lab investigates complex ecological dynamics from microbial community interactions using the fruit fly  Drosophila melanogaster. The fruit fly gut carries numerous microbial species, which can be cultured in the lab. The goal is to understand the gut ecology and how it relates to host health, among other questions, by taking advantage of the fast time-scale and ease of studying the fruit fly in controlled experiments. 
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Nick Konidaris

Nick Konidaris is a staff scientist at the Carnegie Observatories and Instrument Lead for the SDSS-V Local Volume Mapper (LVM). He works on a broad range of new optical instrumentation projects in astronomy and remote sensing. Nick's projects range from experimental to large workhorse facilities. On the experimental side, he recently began working on a new development platform for the 40-inch Swope telescope at Carnegie's Las Campanas Observatory that will be used to explore and understand the explosive universe.

 Nick and his colleagues at the Department of Global Ecology are leveraging the work on Swope to develop a new airborne spectrograph that will be used to provide a direct

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Michael Walter, Director

Experimental petrologist Michael Walter became director of the Geophysical Laboratory beginning April 1, 2018. His recent research has focused on the period early in Earth’s history, shortly after the planet accreted from the cloud of gas and dust surrounding our young Sun, when the mantle and the core first separated into distinct layers. Current topics of investigation also include the structure and properties of various compounds under the extreme pressures and temperatures found deep inside the planet, and information about the pressure, temperature, and chemical conditions of the mantle that can be gleaned from mineral impurities preserved inside diamonds.

Walter had been at

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Guoyin Shen

Guoyin Shen's research interests lie in the quest to establish and to examine models for explaining and controlling the behavior of materials under extreme conditions. His research activities include investigation of phase transformations and melting lines in molecular solids, oxides and metals; polyamorphism in liquids and amorphous materials; new states of matter and their emergent properties under extreme conditions; and the development of enabling high-pressure synchrotron techniques for advancing compression science. 

He obtained a Ph.D. in mineral physics from Uppsala University, Sweden in 1994 and a B.S. in geochemistry from Zhejiang University, China in 1982. For more

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