Carole L. Browne, Professor of Biology
B.S., University of Hartford
Ph.D., Syracuse University

Office: 003 Winston
Phone: (336) 758-5318

Email: browne@wfu.edu

Research Area
Cell and Developmental Biology, Cytoskeleton, cell cycle, Hsps

 
What I do on my summer vacation

Along with Dr. Michael Tytell of the Wake Forest University School of Medicine, each summer I conduct research and direct the Marine Models in Biological Research Program (MMBR) at the Marine Biological Laboratory (MBL) in Woods Hole, Massachusetts. The MMBR program is a nine-week intensive research experience for advanced undergraduates. Students attend lectures and seminars, and conduct individual research projects under the guidance of faculty mentors drawn from the MBL and other institutions throughout the country. MMBR is an REU program (Research Experience for Undergraduates) funded by the National Science Foundation.

Students receive room and board, research expenses, and a stipend. For more information on the MMBR program, check out our web site at http://www.wfu.edu/~browne/mmbr/.

 


MBL, Wood's Hole

Research Interests

My laboratory works on the role of second messengers in signaling cell cycle events. For a number of years we studied cAMP-dependent phosphorylation during mitosis

in cultured cells and in fertilized sea urchin eggs. More recently, we studied patterns of Ca++ release during the cell cycle and in early development in sea urchins, demonstrating a release of calcium prior to nuclear envelope breakdown in fertilized eggs.

The photoprotein aequorin, which luminesces upon binding Ca++, was microinjected into cells and photon release was detected by an image photon detector attached to a miroscope. The temporal and spatial pattern of photon release was analyzed by computer to determine the localization, timing, and pattern of Ca++ release within the cell. In other experiments, microinjected calcium buffers are used to control intracellular free Ca++ concentration to determine the dependence of cell cycle events on free Ca++.


Sea urchins
The coelomic fluid of sea urchins contains motile, phagocytic cells called coelomocytes that undergo a dramatic spreading reaction when physically stressed or placed in hypotonic medium. The ability of coelomocytes to rapidly and extensively remodel their cytoskeleton in response to external stimuli suggested this as another model for testing the functional effects of exogenous Hsp. We have demonstrated that Hsp 70 inhibits the injury response of sea urchin coelomocytes, suggesting that it acts at the cell surface or is internalized in such a way as to inhibit signals regulating the polymerization of the cytoskeleton. 

Most recently, working in collaboration with Dr. Michael Tytell of the Wake Forest University School of Medicine, we have been using the sea urchin egg as a model system for studying the effect of exogenous heat shock protein (Hsp) on cells. Hsps are molecular chaperones involved in protein folding and translocation in response to physical stresses and during immune and inflammatory responses. Recently it has become clear that they also play a role in regulating the cell cycle. Although Hsps are best understood in the context of their intracellular actions, evidence suggests that they can be passed from cell to cell, expressed on plasma membranes, and taken up from the extracellular medium. Thus exogenous application of Hsps might have clinical benefits. Exogenous Hsp is taken up by fertilized eggs of the sea urchin Lytechinus variegatus, leading to a shortening of the first cell cycle after fertilization. The ability of Hsp to decrease cell cycle time is correlated with their ability to protect proteins against heat-induced denaturation.
 

Selected Publications

Carole L. Browne, Justin B. Swan and Michael Tytell. The effect of exogenous heat shock protein on the cell cycle of fertilized sea urchin eggs. submitted for publication

Carole L. Browne, Ellen E. Rankin, Hayes Calvert, and Michael Tytell. The effect of exogenous heat shock protein 70 on actin and tubulin networks in sea urchin coelomocytes, coming soon

Silver, W.L. and Browne, C.L. (2000) Integration of laboratory exercises in development and neurobiology courses using the Xenopus oocyte expression xsystem. J. Industrial Microbiol. Biotech. 24:353-358.

Browne, C.L., Creton R., Karplus, E., Mohler, P.M., Palazzo, R.E., and Miller A.L. 1996. Analysis of the Calcium Transient at NEB During the First Cell Cycle in Dividing Sea Urchin Eggs. Biol. Bull. 191:5-16.

Browne, C.L., Jaffe, L.E., Palazzo, R.E. and Miller, A.L. 1994. Visulaization of the NEB calcium pulses in sea urchin eggs.

Browne, C.L., Miller, A.L., Palazzo, R.E., and Jaffe, L.F. 1992. On the calcium pulse during nuclear envelope breakdown (NEB) in sea urchin eggs. Biol. Bull. 183:370-372.

Browne, C.L., Bower, W.A., Palazzo, R.E. and Rebhun, L.I. 1990. Inhibition of mitosis in fertilized sea urchin eggs by inhibition of the cAMP-dependent protein kinase. Exp. Cell Res. 188:122-128.

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