The Donald Brown laboratory uses  amphibian metamorphosis to study complex developmental programs such as the development of vertebrate organs. The thyroid gland secretes thyroxine (TH), a hormone essential for the growth and development of all vertebrates including humans. To understand TH, director emeritus Donald Brown 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.

 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. 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. Over the years the lab has developed a strategy that is generally applicable to the analysis of complex programs, using TH induced metamorphosis in Xenopus laevis as a model. They have identified genes that are regulated by TH in a variety of tissues and organs by hybridizing probes with micro arrays.

Brown has been widely recognized for his contributions to cell biology. In 2012 he received the prestigious Lasker-Koshland Special Achievement Award in Medical Science.  In 1996 he received the E. B. Wilson Medal of the American Society for Cell Biology. Columbia University honored him with the Louisa Gross Horwitz Prize in 1985. Also in 1985, he was the recipient of the Rosenstiel Award in Basic Biomedical Science from Brandeis University. The New York Academy of Sciences awarded him the Boris Pregel Award for Biology in 1977. Brown is also founder and president of the Life Sciences Research Foundation.

Brown received his M. S. and M. D. in biochemistry from the University of Chicago Medical School. He had fellowships at NIH before coming to Carnegie in 1961 as a fellow. He became a staff member in 1962 and director in 1976 until 1994, at which time he became a staff member again. For more see Brown lab


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Patellar tendon 30 days after an injury courtesy of Tyler Harvey.
November 25, 2019

Baltimore, MD—The buildup of scar tissue makes recovery from torn rotator cuffs, jumper’s knee, and other tendon injuries a painful, challenging process, often leading to secondary tendon ruptures. New research led by Carnegie’s Chen-Ming Fan and published in Nature Cell Biology reveals the existence of tendon stem cells that could potentially be harnessed to improve tendon healing and even to avoid surgery.

“Tendons are connective tissue that tether our muscles to our bones,” Fan explained. “They improve our stability and facilitate the transfer of force that allows us to move. But they are also particularly susceptible to injury and damage.

Kamena Kostova, courtesy Navid Marvi, Carnegie Institution for Science
October 1, 2019

Baltimore, MD— Carnegie biologist Kamena Kostova has been selected for the Director’s Early Independence Award from the National Institutes of Health, which is designed to provide “exceptional junior scientists” with the opportunity to “skip traditional post-doctoral training and move immediately into independent research positions.”

Kostova is one of 13 recipients of the 2019 Early Independence Award. The recognition is part of a suite of four that comprise the NIH Director’s High-Risk, High-Reward Research Program, which honors “highly innovative biomedical or behavioral research proposed by extraordinarily creative scientists.

GDNF repairs aged muscle stem cells courtesy of Liangji Li.
September 30, 2019

Washington, DC— An age-related decline in recovery from muscle injury can be traced to a protein that suppresses the special ability of muscle stem cells to build new muscles, according to work from a team of current and former Carnegie biologists led by Chen-Ming Fan and published in Nature Metabolism.

Skeletal muscles have a tremendous capacity to make new muscles from special muscle stem cells. These “blank” cells are not only good at making muscles but also at generating more of themselves, a process called self-renewal. But their amazing abilities diminish with age, resulting in poorer muscle regeneration from muscle trauma.

The research team—

This image captures the bright blue light (chemiluminesc ence) emitted by the NanoLuc protein in LipoGlo zebrafish. It is is provided courtesy of James Thierer.
July 31, 2019

Baltimore, MD—A newly developed technique that shows artery clogging fat-and-protein complexes in live fish gave investigators from Carnegie, Johns Hopkins University, and the Mayo Clinic a glimpse of how to study heart disease in action. Their research, which is currently being used to find new drugs to fight cardiovascular disease, is now published in Nature Communications.

Fat molecules, also called lipids, such as cholesterol and triglycerides are shuttled around the circulatory system by a protein called Apolipoprotein-B, or ApoB for short. These complexes of lipid and protein are called lipoproteins but may be more commonly known as “bad cholesterol.”

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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 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

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.

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

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

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

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.