Approximately half of the gene sequences of human and mouse genomes comes from so-called mobile elements—genes that jump around the genome. Much of this DNA is no longer capable of moving, but is likely “auditioning”  perhaps as a regulator of gene function or in homologous recombination, which is a type of genetic recombination where the basic structural units of DNA,  nucleotide sequences, are exchanged between two DNA molecules to  repair  breaks in the DNA  strands. Modern mammalian genomes also contain numerous intact movable elements, such as retrotransposon LINE-1, that use RNA intermediates to spread about the genome. 

Given the crucial role of the precursor cells to egg and sperm, called germ cells, to continue a species, their genomes represent a particularly attractive target for mobile elements. One lab looks at the uncontrolled activity of retrotransposons, which causes new mutations and even kill germ cells, which is countered by specialized defensive mechanisms regulating LINE-1 elements through the analysis of function of Maelstrom, a protein found in many species, which is implicated in silencing jumping genes in flies and mice by means of specialized small RNAs known as Piwi-interacting RNAs (or piRNAs).  The group is trying to uncover and understand how LINE-1 elements impact germ cells during normal development.

Scientific Area: 
Genetics & Developmental Biology
Reference to Person: 
Alex Bortvin

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Super-resolution image of fly gut crypts colonized by the native Lactobacillus (red) and Acetobacter (green) bacteria. Fly cell nuclei appear blue. Image is courtesy of Benjamin Obadia.
How microbial interactions shape our lives
December 4, 2018

Baltimore, MD—The interactions that take place between the species of microbes living in the gastrointestinal system often have large and unpredicted effects on health, according to new work from a team led by Carnegie’s Will Ludington. Their findings are published this week in Proceedings of the National Academy of Sciences.

The gut microbiome is an ecosystem of hundreds to thousands of microbial species living within the human body.  The sheer diversity within the human gut presents a challenge to cataloging and understanding the effect these communities have on our health.

Biologists are particularly interested in determining whether or not the

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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

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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

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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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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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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,

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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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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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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

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