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

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 of the protein that makes

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

 

 

 

September 20, 2018

Baltimore, MD— Body organs such as the intestine and ovaries undergo structural changes in response to dietary nutrients that can have lasting impacts on metabolism, as well as cancer susceptibility, according to Carnegie’s Rebecca Obniski, Matthew Sieber, and Allan Spradling.

Their work, published by Developmental Cell, used fruit flies, which are currently the most-sensitive experimental system for such detecting diet-induced cellular changes that are likely to be similar in mammals.

There are three major types of cells in fruit fly (and mammalian) intestines: Stem cells, hormone-producing cells, and nutrient-handling cells. Think of the stem cells as blanks, which are

September 18, 2018

Ethan Greenblatt, a senior postdoctoral associate in Allan Spradling’s lab at the Department of Embryology, has been awarded the eleventh Postdoctoral Innovation and Excellence Award. Greenblatt has made a major impact on biological science, particularly with his research identifying genetic factors underlying fragile X syndrome, the most common cause of autism.

Recipients of these postdoctoral awards are given a cash prize for their exceptionally creative approaches to science, strong mentoring, and contributing to the sense of campus community. A celebration is also held in their honor. These awards are made through nominations from the departments and are chosen by the Office

No content in this section.

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

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. 

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 used to provide a direct

Experimental petrologist Michael Walter became director of the Geophysical Laboratory beginning April 1, 2018. His recent research has focused on the period early in Earth’s history, shortly after the planet accreted from the cloud of gas and dust surrounding our young Sun, when the mantle and the core first separated into distinct layers. Current topics of investigation also include the structure and properties of various compounds under the extreme pressures and temperatures found deep inside the planet, and information about the pressure, temperature, and chemical conditions of the mantle that can be gleaned from mineral impurities preserved inside diamonds.

Walter had been at

Guoyin Shen's research interests lie in the quest to establish and to examine models for explaining and controlling the behavior of materials under extreme conditions. His research activities include investigation of phase transformations and melting lines in molecular solids, oxides and metals; polyamorphism in liquids and amorphous materials; new states of matter and their emergent properties under extreme conditions; and the development of enabling high-pressure synchrotron techniques for advancing compression science. 

He obtained a Ph.D. in mineral physics from Uppsala University, Sweden in 1994 and a B.S. in geochemistry from Zhejiang University, China in 1982. For more