[ Research Interests ] [ Representative Publications ]

Joseph G. Gall Staff Member Department of Embryology, Carnegie Institution of Washington Adjunct Professor Department of Biology B.S. Yale University Ph.D. Yale University

Carnegie Institution of Washington 3520 San Martin Drive Baltimore, MD 21218 U.S.A. Office Telephone: Lab Telephone: Department Fax: Email: 410.554.1217 410.554.1228 410.243.6311 gall@ciwemb.edu Carnegie Institution of Washington

Research Interests Many molecular processes in the cytoplasm take place in or on subcellular organelles, such as the mitochondria, Golgi vesicles, and endoplasmic reticulum. The same is probably true for the nucleus, although, except for the chromosomes and nucleoli, subnuclear organelles have been poorly defined. Our studies concern the role of nuclear organelles in the synthesis and processing of RNA. We are concentrating 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, particular immunofluorescent staining, in situ hybridization, labeling of proteins with green fluorescent protein, and confocal microscopy have brought rapid progress. We now know that Cajal bodies contain many factors involved in transcribing and modifying both pre-messenger RNA and pre-ribosomal RNA. Since neither of these processes itself takes place in the Cajal body, we think that the Cajal body is a site for assembly of factors required for transcription and RNA processing. For much of the work in our lab we use the giant nucleus, or germinal vesicle (GV), of the amphibian oocyte, whose large size makes it ideal for both biochemical and cell biological studies. Everything in the GV is on a grand scale compared to a typical somatic nucleus. It contains the so-called lampbrush chromosomes, giant structures in which actively transcribing genes are visible by conventional light microscopy. A GV also contains over 1000 nucleoli and 50-100 Cajal bodies. The Cajal bodies are many times larger in the GV than in somatic nuclei, permitting a variety of biochemical and biophysical measurements that otherwise would be impossible. The general lesson from our studies is that complex molecular events in the nucleus, like those in the cytoplasm, occur in or on organelles that may be large enough to study by conventional light microscopy. Exactly where these events take place and how the structure of the nucleus contributes to their regulation are important aspects of nuclear physiology. Representative Publications Handwerger, K.E., Murphy, C., and Gall, J.G.  (2003). Steady-state dynamics of Cajal body components in the Xenopus germinal vesicle. J. Cell Biol. 160, 495-504. Handwerger, K.E., Wu, Z., Murphy, C., and Gall, J.G. (2002). Heat shock induces mini-Cajal bodies in the Xenopus germinal vesicle. J Cell. Sci. 115, 2011-2020. Murphy, C., Wang, Z, Roeder, R.G., and Gall, J.G. (2002). RNA polymerase III in Cajal bodies and lampbrush chromosomes of the Xenopus oocyte nucleus.  Mol. Biol. Cell 13, 3466-3476. Doyle, O., Corden, J.L., Murphy, C., and Gall, J.G. (2002). The distribution of RNA polymerase II largest subunit (RPB1) in the germinal vesicle. J. Struct. Biol. 140, 154 166. Morgan, G.T., Doyle, O., Murphy, C., and Gall, J.G. (2000). RNA polymerase II in Cajal bodies of amphibian oocytes.  J. Struct. Biol.  129, 258-268. Gall, J.G.  (2000).  Cajal bodies: the first 100 years.  Annual Review of Cell and Developmental Biology, 16, 273-300. Gall, J.G., Bellini, M., Wu, Z., and Murphy, C. (1999). Assembly of the nuclear transcription and processing machinery: Cajal bodies (coiled bodies) and transcriptosomes. Mol. Biol. Cell 10, 4385-4402. Gall, J. G. and Murphy, C. (1998). Assembly of lampbrush chromosomes from sperm chromatin. Mol. Biol. Cell 9, 733-747.

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