Gary Wessel

..These data help explain some of the classic functions ascribed to the hyalin protein in early development and now enable investigators to focus on the mechanisms of cell interactions with the hyaline layer...

..We conclude from these studies that maturation promoting factor (MPF) activation stimulates vesicle association with microfilaments, and is a key regulatory step in the coordinated translocation of cortical granules to the egg cortex...

..A recent conference in honor of his contributions stimulated this overview. We highlight the major cell surface changes that occur in echinoderms, one of Just's preferred research organisms...

..This review will highlight the fundamental protocols to enable a new investigator to perform an array of approaches on this organism, including oocyte isolation, microinjection, and even single cell quantitative PCR...

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..It is hypothesized that YP30 participates in the packaging and storage of major yolk protein during oogenesis, or in the utilization of the major yolk protein in development...

..Recent progress at the molecular level should soon allow us to explain the seminal experimental observations made in this embryo over a hundred years ago...

..Furthermore, accumulation of germ line determinants selectively in small micromere descendents supports the hypothesis that these cells contribute to the germ line...

..This study elucidated that genes involved in the RNAi silencing pathway have dynamic expression and, thus, may have regulatory roles during germ cell development and embryogenesis...

..These results suggest that germline specification depends on the small micromeres, either directly as lineage products, or indirectly by signaling mechanisms emanating from the small micromeres or their descendants...

..These results will be instrumental in the future to functionally test the SNARE regulators associated with multiple membrane fusion events...

..Thus, p160 is a key candidate for a vitelline-layer linker protein, the selective proteolysis of which functions in the block to polyspermy in the sea urchin egg...

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..Together, these results emphasize how transglutaminases can coordinate the activities of other enzymes during extracellular matrix transmogrifications...

..These distinctly trafficked variants reunite after cortical granule secretion at fertilization. Together, they help coordinate assembly of the functional fertilization envelope, whose proteome is now defined in full...

..We propose that oogenesis is reliant on a dynamic gene regulatory network that includes oocyte-specific transcriptional regulators...

..Phylogenetic analysis of the enzymatic modules in Udx1 suggests a potentially conserved role for the dual oxidase family in hydrogen peroxide production and regulation during fertilization...

..As we propose here, this conservation implies the existence of an underlying germline multipotency program in these cell types that has a previously underappreciated and conserved function in maintaining multipotency...

..Identification of this same protein in other developmental stages also shown here will be important for interpreting stimulus-dependent secretory events for signaling throughout embryogenesis...

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..Their large size (1.3-microm diameter), vast number, and ease of manipulation enable several unique approaches to study general secretion mechanisms...

..Thus, specific free-radical chemistry is essential for establishing the embryonic microenvironment of early development...

..These studies provide a foundation to further test specific hypotheses of the G-protein mediated regulation of oocyte maturation, fertilization, and early development in the sea urchin...

..This finding is consistent with progressive cell differentiation in the embryo. Taken together, these results suggest that PcG genes are conserved in S. purpuratus and are actively expressed during early embryogenesis...

..This work, in combination with other recent results in Ilyanassa and Platynereis dumerilii, suggests the presence of a conserved molecular program underlying both primordial germ cell and multipotent cell specification and maintenance...

..Inhibition of suH(1)R function decreases the maintenance, but not the amplitude, of the Ca(2+) transient and suggests that it is an integral part of the overall pathway leading to egg activation at fertilization in sea urchins...

..I saw this envelope manifest when in contact with a very small number of spermatozoids (three or four, sometimes even one only)...

..In addition, these results demonstrate that the entire population of yolk platelets is competent to receive new yolk protein input, suggesting that they are all made simultaneously during oogenesis...

..Thus, CGSP1 is proteolytically active only when secreted, due to the low pH of the cortical granules, and it has a small population of targets for cleavage within the cortical granules...

..Here we integrate the cellular and molecular events necessary to form this fertilization envelope within the first few minutes of a new embryo's life...

..We also find that cyclin A can functionally substitute for cyclin B in early embryos but not in oocytes. These studies provide a foundation for understanding the mechanism of meiotic maturation independent of the zygotic cell cycle...

..Thus, these secretory granules are tethered to their target plasma membrane by a static, catalytic fusion complex that maintains a hemifused membrane intermediate...

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..Using this specific biochemical approach, we are able to separate distinct pathways of endocytosis during oogenesis and learn that dynamin-mediated endocytosis is responsible for MYP endocytosis but not fluid-phase uptake...

..We suggest that one of MYP's transferrin-like properties is to shuttle iron to developing germ cells...

..We also consider the evolution of alternative or radical techniques, including physiological polyspermy, with respect to our ability to describe a parsimonious guide to fertilization...

..We propose integration of the G-protein input into the framework of signaling at sea urchin fertilization...

..These results support the growing evidence that AGS is a universal regulator of asymmetric cell divisions in embryos...

..These results suggest that in sea urchins, cyclin D and cdk4 are required for normal development and perhaps the patterning of the developing embryo, but may not be directly involved in regulating entry into the cell cycle...

..This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes...

..We conclude that Rho association with the cortical granules is a critical regulatory step in their translocation to the egg cortex...

..These findings suggest that lineage-specific expansions may be an important component of genomic evolution in signal transduction...

..SNAREs, synaptotagmin, and their immediate binding partners are critical to exocytosis at a stage other than membrane fusion, although they may still influence the triggered steps...

..Our results will have particular significance to clinical IVF predictions in human reproductive health. ..

..Our results will have particular significance to clinical IVF predictions in human reproductive health. ..

..Our results will have particular significance to clinical IVF predictions in human reproductive health. ..

..We will focus on proteins that interact with SNARE homologues and of rab 3, and address both the mechanism for stimulating exocytosis, as well as the molecular clamp that blocks exocytosis until fertilization. ..

..The requested instrument would significantly enhance the research productivity of the broad, interdisciplinary community of researchers described here, and greatly improve the biological image capabilities in the region. ..

..The hypothesis will be tested that the extracellular matrix derived from maternal stores is important in the stimulation of zygotic ECM synthesis. This study will include the characterization of several novel ECM molecules. ..

..Ourresultswillhaveparticular significancetoclinicalIVFpredictionsinhumanreproductivehealth. ..