Priess, James

Faculty Profile

First Name: 
Last Name: 
[field_fname-formatted] [field_lname-formatted]
Primary Institution: 
Basic Sciences
Mail/Box #: 

Box 358080/A3-013

Office Location: 

A3 107 Weintraub Building FHCRC

Office Phone: 
(206) 667-2871
Alternate Phone: 
(206) 667-4525

Research Summary: 

We use the nematode C. elegans as a model system for studying developmental biology. Our current research focuses on how embryonic cells assemble into epithelial tubes, and on the development of adult germ cells.  The digestive tract is comprised largely of two, linked epithelial tubes, a muscular pharynx, and the intestine.  Precursor cells for both organs are specified during early embryogenesis through a highly orchestrated sequence of events that includes asymmetrically localized, maternally-provided factors, cell-cell interactions, and a remarkable recursive asymmetry in the localization of the transcription factor POP-1/TCF.  If cultured in vitro and in isolation, the precursor cells form rounded, polarized cysts.  In the intact embryo, by contrast, the precursors generate interconnected, epithelial tubes.   Using live cell imaging, 3D graphics, genetics and experimental cell biology, we showed that the pharyngeal precursor cells first aggregate into a bilaterally symmetrical primordium we term the double plate. Cells surfaces on the exterior of the double plate appear to be signaled by laminin that is secreted by surrounding cells, and the double plate cells respond by localizing the polarity PAR proteins to their opposite, future apical surfaces.  The apical surfaces contract, causing the cells to adopt wedge shapes and transforming the double plate into a tube. The final positioning of the cells is controlled by a highly patterned series of cell intercalations, effectively rotating specific cell types into their correct positions along the tube.  For example, one cell called pm8 intercalates along the entire circumference of the developing tube, finally meeting itself and fusing into a single, donut-shaped cell.   In current studies, we are using the tools of C. elegans genetics to identify genes involved in patterning the intercalations.  
In C. elegans larvae and adults, germ nuclei are associated with large, discrete structures called P granules; these contain several types of proteins, including multiple proteins involved in mRNA regulation.  We found that the nuclear pores on germ nuclei are clustered beneath P granules, and that most of the nascent mRNA traffics through P granules.  Both P granules and conventional nuclear pores contain proteins with FG (phenylalanine-glycine) repeats; in nuclear pores, FG-repeat proteins are involved in transport to and from the nucleus.  Thus, mRNAs emerging from germ cell nuclear pores traffic through a second FG-rich zone of potential regulatory factors (the P granule), before entering the general cytoplasm.  In mex-3, gld-1 double mutants, P granule loss is correlated with the formation of a germline teratoma, with germ cells differentiating spontaneously into somatic cell types, such as muscles and neurons.  In current studies, we are exploring the behavior of germ cells during programmed cell death (apoptosis), and interactions between germ cells and retroviruses.

Short Research Description: 
embryogenesis and germ cell development
Areas of Interest: 
Developmental Biology, Stem Cells & Aging
<p> Developmental Biology, Genetics, Molecular Biology, Genetics, Molecular Biology</p>

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