Research group of Professor Susan Strome

Research group of Professor Susan Strome

From left to right: Dustin Updike (Postdoc), Stephanie Hachey (Lab Technician), Andreas Rechsteiner (Associate Project Scientist/Bioinformaticist), Teruaki Takasaki (Postdoc), Lisa Petrella (Postdoc), Jacob Garrigues (Graduate Student), Laura Gaydos (Graduate Student) and Susan Strome (Principal Investigator)

Professor Susan Strome leads a team based in the Department of Molecular Cell and Developmental (MCD) Biology at the University of California, Santa Cruz. The Strome lab studies the regulation of germ cell development in C. elegans, particularly the role of germline-specific cytoplasmic P granules. They also collaborate with Bill Saxton's lab, also at the University of California, Santa Cruz, to study mitosis and patterning in early embryos.

Susan first discovered P granules in the C. elegans germline whilst working as a postdoctoral researcher in Bill Wood's lab at the University of Colorado, Boulder. Susan then went on to hold positions as Assistant and Associate Professor at Indiana University. In 1998, she was named as a Guggenheim Fellow and took a sabbatical in the Laboratory of Molecular Biology at the University of Wisconsin, Madison. In the same year, Susan was appointed Professor in the Department of Biology at the Indiana University and was later made Chancellor's Professor. In 2007, after spending another sabbatical in Santa Cruz, Susan, along with Bill, made the decision to relocate their labs to the University of California, Santa Cruz.

The germline serves the unique and critical role of producing gametes and offspring. Researchers in the Strome lab are investigating the molecular mechanisms by which these germ cells establish and maintain their identity, immortality and totipotency. Research is currently focused on two regulatory systems: regulators of chromatin organization that are required for germline immortality, and control of RNA metabolism by germline-specific cytoplasmic P granules. The model organism C. elegans is used in this work as the adult worm contains only ~1000 somatic cells and ~1000 germ cells, organized into a relatively simple body plan. A wide variety of techniques are used in the lab, including forward genetics, RNAi, imaging, molecular biology, biochemistry, and whole genome microarray-based technologies.

Germ granules are distinctive organelles found in the germ cells of most, if not all species. Segregation of these granules to the germline was first observed in fruit flies, frogs, and nematodes, suggesting their involvement in germline development. The Strome lab has demonstrated that the C. elegans germ granules (P granules) are indeed required for fertility. There are approximately 3 dozen proteins known to associate with P granules, all of which are predicted to bind RNA and several of which have been shown to be required for germline development. The current working model is that germ granules control the trafficking, translation and/or stability of mRNAs in the germline. Research is focused on identifying additional P granule components, defining the pathway of granule assembly, elucidating the roles of individual granule components, and using microarray analysis to investigate RNA regulation. Through this research, Susan and her colleagues aim to provide a better understanding of the composition and functions of these intriguing and still mysterious germline-specific organelles.

Dr. Dustin Updike is a post-doctoral researcher in the Strome lab. Dustin obtained his B.S. in Molecular Biology from the University of Wyoming in Laramie, in 1999. He then studied for a PhD in Dr. Susan Mango's lab at the University of Utah, Salt Lake City, where he investigated organogenesis in C. elegans. In 2007, he started his postdoctoral position in Susan Strome's lab.

One of Dustin's projects has been to identify genes that affect the stability, localization and function of P granules. To do this, he performed a genome-wide RNAi screen in C. elegans to identify GFP-tagged P granule defects. Many of the genes that were identified fall into specific classes with shared P granule phenotypes, allowing a better understanding of how cellular processes converge on P granule assembly and function. Dustin is currently using Volocity high performance 3D imaging software in his research.

Dustin says "P granules are fascinating. Understanding how P granules work is critical for understanding how cellular immortality and totipotency is retained, gained and lost.  Since Susan's discovery of P granules over 25 years ago, the lab has made significant advances toward this understanding. Using Volocity, we can easily visualize the volume, size, and spatial distributions of P granules, observe P granule dynamics in developing worms, and compare and quantify these attributes in different genetic backgrounds."

Movie
The movie shows a series of fixed images from a C. elegans embryo, with P granules in green. The 3D properties of these P granules were examined using Volocity software. The P granules segregate to the primordial germ cells during embryogenesis. Germ granules are thought to act as germline determinants that endow the germline with its immortal and totipotent properties. PGL-1 (a constitutive P granule protein) is shown in green, nuclear pores in red and DNA in blue (movie courtesy of Dr. Dustin Updike).

More movies made using Volocity can be viewed on Dustin's YouTube page at http://www.youtube.com/user/silverscreendu

To find out more about research in the Strome lab, please visit http://bio.research.ucsc.edu/people/strome/index.html