Professor of Biology, Amherst College
Ph.D.: Harvard University
Activation of Sperm Nuclei at Fertilization
During maturation of most animal sperm cells, sperm-specific nuclear proteins replace somatic histones, DNA synthesis, RNA synthesis, and cell division cease, and the chromatin becomes highly compacted in preparation for the sperm cell’s journey to the egg. After fertilization, the dormant sperm nucleus must become activated in order to participate in normal cellular events such as replication, transcription, and mitosis. The deactivation of the male germ cell nucleus during spermatogenesis and its reactivation following fertilization can serve as model systems for the study of gene activity, replication, chromatin and nuclear envelope assembly, and higher order chromatin structure.
We use in vitro cultures of sea urchin testis fragments, polyspermically fertilized eggs, microinjection, and cell-free systems to study at the biochemical level transitions in nuclear composition, architecture, and activity during spermatogenesis and fertilization. Using techniques such as gel electrophoresis, in situ hybridization, fluorescence microscopy, flow cytometry, organ culture, and subcellular fractionation, we are attempting to understand the molecular basis of sperm nuclear differentiation and male pronuclear formation.
Teresa Barona, Richard D. Byrne, Trevor R. Pettitt, Michael J. O. Wakelam, Banafshe Larijani, and Dominic L. Poccia (2005). Diacylglycerol induces fusion of nuclear envelope membrane precursor vesicles. Journal of Biological Chemistry 280: 41171-41177.
Richard D. Byrne, Teresa M. Barona, Marie Garnier, Grielof Koster, Matilda Katans, Dominic L. Poccia, and Banafshe Larijani (2005). Nuclear envelope assembly is promoted by phosphoinositide-specific phospholipase C with selective recruitment of phosphatidylinositol-enriched membranes. Biochemical Journal 387: 393-400.
S. Stephens '99, B.Beyer '97, U. Balthazar-Stablein '00, R. Duncan, M. Kostacos '94, M. Lukoma '98, G. R. Green and D. Poccia (2002). Two kinase activities are sufficient for sea urchin sperm chromatin decondensation in vitro. Molecular Reproduction and Development 62: 496-503.
Banafshe Larijani, Teresa M. Barona and Dominic L. Poccia (2001). Role for phosphatidylinositol in nuclear envelope formation. Biochemical Journal 356: 495-501.
Green, G. R., R. R. Ferlita, W. F. Walkenhorst and D. L. Poccia (2001). "Linker DNA destabilizes condensed chromatin." Biochem Cell Biol 79(3): 349-63.
Larijani, B., T. M. Barona and D. L. Poccia (2001). "Role for phosphatidylinositol in nuclear envelope formation." Biochem J 356(Pt 2): 495-501.
Larijani, B., D. L. Poccia and L. C. Dickinson (2000). "Phospholipid identification and quantification of membrane vesicle subfractions by 31P-1H two-dimensional nuclear magnetic resonance." Lipids 35(11): 1289-97.
Collas, P., T. Barona and D. L. Poccia (2000). "Rearrangements of sea urchin egg cytoplasmic membrane domains at fertilization." Eur J Cell Biol 79(1): 10-6.
Collas, P. and Poccia, D. (1998) Methods for Studying In Vitro Assembly of Male Pronuclei Using Extracts from Marine Invertebrates: Sea Urchins and Surf Clams. Meth. Cell Biol. 53, 417-452.
Poccia, D. and Collas, P. (1997) Nuclear Envelope Dynamics During Male Pronuclear Development. Devel. Growth Differ. 39, 541-550.
Collas, P., Thompson, L., Fields, A.P., Poccia, D.L. and Courvalin, J.-C. (1997) PKC-Mediated Interphase Lamin B Phosphorylation and Solubilization. J. Biol. Chem. 272, 21274-21280.
Collas, P., Courvalin, J.-C. and Poccia, D.L. (1996) Targeting of Membranes to Sea Urchin Sperm Chromatin is Mediated by an LBR-Like Integral Membrane Protein. J. Cell Biol. 135, 1715-1725.
Collas, P. and Poccia, D.L. (1996) Conserved Binding Recognition Elements of Sperm Chromatin, Sperm Lipophilic Structures and Nuclear Envelope Precursor Vesicles. Eur J. Cell Biol. 71, 22-32.