The Fan laboratory studies the molecular mechanisms that govern mammalian development, using the mouse as a model. They use a combination of biochemical, molecular and genetic approaches to identify and characterize signaling molecules and pathways that control the development and maintenance of the musculoskeletal and hypothalamic systems.

The musculoskeletal system provides the mechanical support for our posture and movement. How it arises during embryogenesis pertains to the basic problem of embryonic induction. How the components of this system are repaired after injury and maintained throughout life is of biological and clinical significance. They study how this system is generated and maintained.

The hypothalamus is an essential brain center that maintains a balance in multiple physiological processes by modulating pituitary hormone secretions. Two centers of the hypothalamus, called the paraventricular and supraoptic nuclei (PVN and SON), contain various hormone-producing neurons. Studies of these hormones have been instrumental to our understanding of endocrine balance, including the maintenance of bodily fluids and the balance of energy metabolism. Despite the importance of PVN and SON function, molecules that control their embryonic specification, neuronal differentiation, nucleus formation, and neuronal connections are largely unknown.  The lab’s novel approach  to studying embryonic development of the PVN and SON has identified a genetic contributor to feeding regulation and obesity in rodents and humans. These developmental studies of the suggest a new avenue for finding genetic determinants of homeostasis regulation.

Scientific Area: 
Genetics & Developmental Biology
Reference to Person: 
Chen-Ming Fan
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Yixian Zheng
Carnegie’s Zheng wins Moore Foundation support for advancing the frontier of symbiosis research
March 11, 2020

Baltimore, MD— Carnegie’s Director of Embryology Yixian Zheng is one of 15 scientists awarded a grant from the Gordon and Betty Moore Foundation to support research on symbiosis in aquatic systems.

For the past two years, Zheng and her colleagues have been working to elucidate the molecular mechanisms of endosymbiosis in the relationships between coral and jellyfish and the photosynthetic algal species that they host. She has been building on Carnegie’s longstanding tradition of model organism development to begin revealing the genetics underlying the uptake and sustenance of symbiotic dinoflagellates by the soft coral species Xenia.

“I have always

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Illustration courtesy of Navid Marvi and Andres Aranda-Diaz.
Microbiome species interactions reveal how bacteria collaborate to cheat death
March 5, 2020

Baltimore, MD—Antibiotics can make easy work of infections. But how do they affect the complex ecosystems of friendly bacteria that make up our microbiome?

“When a doctor prescribes antibiotics, it sets up a multi-faceted experiment in your gastrointestinal system,” explains Carnegie’s Will Ludington “What can it teach us about the molecular principles of species interactions in nature?”

New work led by Ludington and Stanford University’s K.C. Huang set out to answer this challenging question and discovered a new form of antibiotic tolerance. Their findings, which have important health implications, are published by eLife.

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Bellymount allows researchers to peer into the live tissue of the fruit fly gut.
Eavesdropping on “conversations” between gut stem cells and gut bacteria
March 2, 2020

Baltimore, MD— They say a picture is worth 1,000 words. But what about a real-time window into the complexity of the gastrointestinal system? 

A new research tool allowed biologists to watch in real time the cell renewal process that keeps gut tissue healthy, as well as the interactions between bacterial species that make up the microbiome. Their work, led by Lucy O’Brien and KC Huang of Stanford University and Carnegie’s Will Ludington, was recently published by PLOS Biology.

The system, dubbed Bellymount, allowed researchers to peer into the live tissue of the fruit fly gut and better understand the many complex, overlapping processes occurring

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Fetal Oocyte Attrition prevention, courtesy Marla Tharp and Navid Marvi.
Jumping genes threaten egg cell quality; understanding their activity has implications for fertility and health of future generations.
January 16, 2020

Baltimore, MD— A woman’s supply of eggs is finite, so it is crucial that the quality of their genetic material is ensured. New work from Carnegie’s Marla Tharp, Safia Malki, and Alex Bortvin elucidates a mechanism by which, even before birth, the body tries to eliminate egg cells of the poorest quality. Their findings describing this mechanism are published by Nature Communications.

“Some organisms produce a large number of offspring, many of which don’t survive to adulthood; females in these species continually produce new egg cells throughout their reproductive lives,” Bortvin explained. “But in mammals, females are born with a fixed

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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

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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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The role of organelles in the cell nucleus that synthesize and process RNA

The Gall laboratory studies all aspects of the cell nucleus, particularly the structure of chromosomes, the transcription and processing of RNA, and the role of bodies inside the cell nucleus, especially the Cajal body (CB) and the histone locus body (HLB).

Much of the work makes use of the giant oocyte of amphibians and the equally giant nucleus or germinal vesicle (GV) found in it. He is particularly  interested in how the structure of the nucleus is related to the synthesis and processing of RNA—specifically, what changes occur in the chromosomes and other nuclear components when RNA is synthesized, processed, and transported to the cytoplasm.
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Moises Exposito-Alonso

Evolutionary geneticist Moises Exposito-Alonso joined the Department of Plant Biology as a staff associate in September 2019. He investigates whether and how plants will evolve to keep pace with climate change by conducting large-scale ecological and genome sequencing experiments. He also develops computational methods to derive fundamental principles of evolution, such as how fast natural populations acquire new mutations and how past climates shaped continental-scale biodiversity patterns. His goal is to use these first principles and computational approaches to forecast evolutionary outcomes of populations under climate change to anticipate potential future

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Kamena Kostova

Staff Associate Kamena Kostova joined the Department of Embryology in November 2018. She studies ribosomes, the factory-like structures inside cells that produce proteins. Scientists have known about ribosome structure, function, and biogenesis for some time. But, a major unanswered question is how cells monitor the integrity of the ribosome itself. Problems with ribosomes have been associated with diseases including neurodegeneration and cancer. The Kostova lab investigates the fundamental question of how cells respond when their ribosomes break down using mass spectrometry, functional genomics methods, and CRISPR genome editing.

Kostova received a B.S. in Biology from the

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Sally June Tracy

Sally June Tracy applies cutting-edge experimental and analytical techniques to understand the fundamental physical behavior of materials at extreme conditions. She uses dynamic compression techniques with high-flux X-ray sources to probe the structural changes and phase transitions in materials at conditions that mimic impacts and the interiors of terrestrial and exoplanets. She is also an expert in nuclear resonant scattering and synchrotron X-ray diffraction. She uses these techniques to understand novel behavior at the electronic level.  Tracy received her Ph.D. from the California Institute of

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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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