Yixian Zheng’s lab has a long-standing interest in cell division. In recent years, their findings have broadened their research using animal models, to include the study of stem cells, genome organization, and lineage specification—how stem cells differentiate into their final cell forms. They use a wide range of tools, including genetics in different model organisms, cell culture, biochemistry, proteomics, and genomics.

Cell division is essential for all organisms to grow and live. During a specific time in a cell’s cycle the elongated apparatus consisting of string-like micro-tubules called the spindle is assembled to move the chromosomes into two new cells. Another structure near the cell’s nucleus, the centrosome, is important for creating the microtubules and for assembling the spindle. Researchers are trying to understand the regulation of the spindle assembly, the structure of the centrosome, and how it organizes the microtubules and participates in spindle assembly.

The scientists use the frog Xenopus for their research.  The centrosome consists of a pair of cylinder-shaped structures called centrioles, which are surrounded by a material called pericentriolar material (PCM). Microtubules arise from this PCM. The Zheng scientists discovered a ring complex containing an essential protein component of microtubules called γ -tubulin. They found that the ring complex, named γ TuRC, is essential for centrosomes to form microtubules. They also uncovered an important signaling pathway controlled by a protein made in the nucleolus called GTPase Ran that regulates multiple aspects of cell division.

To study genome organization in development and aging, they use various tools to study how genomes obtain their organization in stem cells and during development. To understand the influence of the process of the cell beginning to shape, called cell morphogenesis, on the eventual type of cell it turns into, the researchers use a technique called pre-implantation mouse embryos. The development of a pre-implanted embryo allows them to discern the first type of cell differentiation, or lineage specification, in a small number of initially similar cells independent of any influence from other tissues. By using live-imaging and computational modeling and tracking, they uncovered unique cellular behaviors that are associated with lineage specification during pre-implantation development, key to analyzing how various physical and chemical changes in the developing cell influence which genes are turned on.

Zheng was a Howard Hughes Medical Investigator from 2000 to 2012. She studied biology as an undergraduate in China before moving to Ohio State University where she received a PhD in 1992. She was a postdoctoral fellow at the University of California, San Francisco from 1992 to 1996, when she moved to Carnegie as a staff scientist and became Acting Director of the department in early 2016.  For more see the Zheng lab

Explore Carnegie Science

Carnegie Science, Carnegie Institution, Carnegie Institution for Science,
July 13, 2017

Baltimore, MD— The brain is the body’s mission control center, sending messages to the other organs about how to respond to various external and internal stimuli. Located in the forebrain, the habenular region is one such message-conducting system. Two new papers from Carnegie scientists explain how the habenulae develop and their unsuspected role in recovering from fear.

Found in all vertebrates, the bilaterally paired habenulae regulate the transmission of dopamine and serotonin, two important chemicals related to motor control, mood, and learning.

Previous research has shown that the habenular system is involved in modulating sleep cycles, anxiety, and pain and reward

Carnegie Science, Carnegie Institution, Carnegie Institution for Science,
July 6, 2017

Washington, D.C.--Yixian Zheng has been selected to direct Carnegie’s Department of Embryology in Baltimore, Maryland. She has been Acting Director since February 1st of 2016.

Carnegie president Matthew Scott remarked, “Yixian has been an exceptional leader of the department as Acting Director. We are extremely pleased that she took on this job permanently.  Her fascinating science, independent thinking, vision, extraordinary management skills, and perfect temperament are a tremendous asset to Carnegie Science.”

The Zheng lab has a long-standing interest in cell division and the cytoskeleton—the lattice arrangement of rods and fibers and motors that gives shape to cells and

May 15, 2017

Washington, D.C.—BioEYES was accepted to participate in a National Science Foundation (NSF) video competition on May 15-22, 2017. BioEYES supporters are encouraged to go to the competition website at stemforall2017.videohall.com and share and vote for the BioEYES video! (Note the guidelines for the three ways to vote. Watch the video directly here http://stemforall2017.videohall.com/p/1025)

Project BioEYES, based at Carnegie’s Department of Embryology in Baltimore, MD, (www.bioeyes.org) uses live zebrafish to teach basic scientific principles, animal development, and genetics to underrepresented students, while training teachers in Science, Technology, Engineering and Mathematics

Carnegie Science, Carnegie Institution, Carnegie Institution for Science
May 8, 2017

Baltimore, MD—Studying how our bodies metabolize lipids such as fatty acids, triglycerides, and cholesterol can teach us about cardiovascular disease, diabetes, and other health problems, as well as reveal basic cellular functions. But the process of studying what happens to lipids after being consumed has been both technologically difficult and expensive to accomplish until now.

New work from Carnegie’s Steven Farber and his graduate student Vanessa Quinlivan debuts a method using fluorescent tagging to visualize and help measure lipids in real time as they are metabolized by living fish. Their work is published by the Journal of Lipid Research.

“Lipids play a vital role

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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.

 

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

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

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

Leopoldo Infante became the director of the Las Campanas Observatory on July 31, 2017.

Since 2009, Infante has been the founder and director of the Centre for Astro-Engineering at the Chilean university. He joined PUC as an assistant professor in 1990 and has been a full professor since 2006. He was one of the creators of PUC’s Department of Astronomy and Astrophysics, and served as its director from 2000 to 2006. He also established the Chilean Astronomical Society (SOCHIAS) and served as its president from 2009 to 2010.

Infante received his B.Sc. in physics at PUC. He then acquired a MSc. and Ph.D. in physics and astronomy from the University of Victoria in Canada.

Guillermo Blanc wants to understand the processes by which galaxies form and evolve over the course of the history of the universe. He studies local galaxies in the “present day” universe as well as very distant and therefore older galaxies to observe the early epochs of galaxy evolution. Blanc conducts a series of research projects on the properties of young and distant galaxies, the large-scale structure of the universe, the nature of Dark Energy—the mysterious repulsive force, the process of star formation at galactic scales, and the measurement of chemical abundances in galaxies.

To conduct this work, he takes a multi-wavelength approach including observations in the UV,

Peter van Keken studies the thermal and chemical evolution of the Earth. In particularly he looks at the causes and consequences of plate tectonics; element modeling of mantle convection,  and the dynamics of subduction zones--locations where one tectonic plate slides under another. He also studies mantle plumes; the integration of geodynamics with seismology; geochemistry and mineral physics. He uses parallel computing and scientific visualization in this work.

He received his BS and Ph D from the University of Utrecht in The Netherlands. Prior to joining Carnegie he was on the faculty of the University of Michigan.

Peter Driscoll studies the evolution of Earth’s core and magnetic field including magnetic pole reversal. Over the last 20 million or so years, the north and south magnetic poles on Earth have reversed about every 200,000, to 300,000 years and is now long overdue. He also investigates the Earth’s inner core structure; core-mantle coupling; tectonic-volatile cycling; orbital migration—how Earth’s orbit moves—and tidal dissipation—the dissipation of tidal forces between two closely orbiting bodies. He is also interested in planetary interiors, dynamos, upper planetary atmospheres and exoplanets—planets orbiting other stars. He uses large-scale numerical simulations in much of his research