The first step in gene expression is the formation of an RNA copy of its DNA. This step, called transcription, takes place in the cell nucleus. Transcription requires an enzyme called RNA polymerase to catalyze the synthesis of the RNA from the DNA template. This, in addition to other processing factors, is needed before messenger RNA (mRNA) can be exported to the cytoplasm, the area surrounding the nucleus.

Although the biochemical details of transcription and RNA processing are known, relatively little is understood about their cellular organization. Joseph G. Gall has been an intellectual leader and has made seminal breakthroughs in our understanding of chromosomes, nuclei and cells for nearly 60 years.   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.

The researchers concentrate on a structure in the nucleus called the Cajal body, so named because it was first described 100 years ago by the Spanish neurobiologist and Nobel laureate Ramon y Cajal. Until recently very little was known about the Cajal body, but modern microscopical techniques  have brought rapid progress. Cajal bodies are now known to contain many factors involved in transcribing and modifying both pre-messenger RNA and pre-ribosomal RNA. Gall thinks that the Cajal body is a site for assembly of factors required for transcription and RNA processing.

Much of the lab’s work is carried out with unlaid eggs removed from the female frog Xenopus. These eggs, called oocytes, are giant cells up to 1.5 millimeters (mm) in diameter with a nucleus, or germinal vesicle (GV), 0.4 mm in diameter. The large GV permits scientists to examine the contents and structure of the nucleus in unprecedented detail.

The lab also used the fruit fly Drosophila cells , which are much smaller than frog cells, but have the advantage that they permit genetic studies on Cajal body components. In Drosophila one can manipulate the genes that encode proteins and RNAs of the Cajal body, and follow the consequences in various embryonic, larval, and adult tissues.

Gall has received numerous awards in acknowledgment of his special contributions, including the Albert Lasker Special Achievement Award in Medical Research, and the Lifetime Achievement Award of the Society for Developmental Biology, among others.

From 1952 to 1964 Gall taught zoology at the University of Minnesota. From 1964 to1983 he was the Ross Granville Harrison Professor of Biology, Professor of Molecular Biophysics and Biochemistry, at Yale University. In1983 he joined the Carnegie Institution as a staff scientist. For more see the Gall lab

Explore Carnegie Science

November 10, 2016

Baltimore, MD—A first-of-its-kind study on almost 20,000 K-12 underrepresented public school students shows that Project BioEYES, based at Carnegie’s Department of Embryology, is effective at increasing students’ science knowledge and positive attitudes about science. Younger students had the greatest attitude changes. The study covered five years and tested students before and after the one-week BioEYES program. The research is published in the November 10, 2016, issue of PLOS Biology.

BioEYES (www.bioeyes.org) uses live zebrafish to teach basic scientific principles, animal development, and genetics. The zebrafish embryo is clear, making it ideal for observations. Each BioEYES

Carnegie Science, Carnegie Institution, Carnegie Institution for Science
November 2, 2016

Baltimore, MD— New work led by Carnegie’s Steven Farber, with help from Yixian Zheng’s lab, sheds light on how form follows function for intestinal cells responding to high-fat foods that are rich in cholesterol and triglycerides. Their findings are published in the Journal of Biological Chemistry.

Enterocytes are specialized cells that line the insides of our intestines. The intestinal surface is like a toothbrush, with lots of grooves and protrusions that allow the cells there to grab and absorb nutrients from food as it is digested, including the lipid molecules from fatty foods. The cells absorb, process, and package these lipids for distribution throughout our bodies. Clearly

Carnegie Science, Carnegie Institution, Carnegie Institution for Science
October 5, 2016

Baltimore, MD---Athletes, the elderly and those with degenerative muscle disease would all benefit from accelerated muscle repair. When skeletal muscles, those connected to the bone, are injured, muscle stem cells wake up from a dormant state and repair the damage. When muscles age, however, stem cell number and function declines, as do both tissue function and regenerative ability.  Carnegie’s Christoph Lepper and team*, including researchers from the University of Missouri, investigated muscle stem cell pool size. In particular, they asked if stem cell number could be increased, and if there would be any associated functional benefits.

Using genetically modified mice, the

September 23, 2016

Washington, D.C.—  Zehra Nizami has been a graduate student and postdoc in Joe Gall’s lab at the Department of Embryology. She is the fourth recipient of the Postdoctoral Innovation and Excellence (PIE) Award, which are made through nominations from the department directors and chosen by the Office of the President. Her career at Embryology includes outstanding accomplishments in the three areas recognized by the PIE Award—science, education, and community service.

Nizami is co-discoverer of a new class of RNA molecules in amphibian egg cells called stable intronic sequence (sis) RNA. These sequences were not anticipated. It was believed for 35 years that introns—bits of DNA that

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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

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

Andrew Newman works in several areas in extragalactic astronomy, including the distribution of dark matter--the mysterious, invisible  matter that makes up most of the universe--on galaxies, the evolution of the structure and dynamics of massive early galaxies including dwarf galaxies, ellipticals and cluster. He uses tools such as gravitational lensing, stellar dynamics, and stellar population synthesis from data gathered from the Magellan, Keck, Palomar, and Hubble telescopes.

Newman received his AB in physics and mathematics from the Washington University in St. Louis, and his MS and Ph D in astrophysics from Caltech. Before becomming a staff astronomer in 2015, he was a

Gwen Rudie studies the chemical and physical properties of very distant, so-called  high-redshift galaxies and their surrounding circumgalactic medium. She is primarily an observational astronomer working on the analysis and interpretation of high-resolution spectroscopy of high-redshift Quasi Stellar Objects and low to medium-resolution near-infrared and optical spectroscopy of high-redshift galaxies. She is interested in understanding the intergalactic medium as a tool for understanding galaxy evolution and the physical properties of very distant galaxies such as the composition of stars and their star formation rates

Rudie received her AB from Dartmouth College and her Ph D