Gary M Wessel

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The germline of multicellular animals is segregated from somatic tissues, which is an essential developmental process for the next generation. Although certain ecdysozoans and chordates segregate their germline during embryogenesis, animals from other taxa segregate their germline after embryogenesis from multipotent progenitor cells. An overlapping set of(More)
An egg-that took weeks to months to make in the adult-can be extraordinarily transformed within minutes during its fertilization. This review will focus on the molecular biology of the specialized secretory vesicles of fertilization, the cortical granules. We will discuss their role in the fertilization process, their contents, how they are made, and the(More)
Two distinct modes of germ line determination are used throughout the animal kingdom: conditional-an inductive mechanism, and autonomous-an inheritance of maternal factors in early development. This study identifies homologs of germ line determinants in the sea urchin Strongylocentrotus purpuratus to examine its mechanism of germ line determination. A list(More)
Vasa is a DEAD-box RNA helicase that functions in translational regulation of specific mRNAs. In many animals it is essential for germ line development and may have a more general stem cell role. Here we identify vasa in two sea urchin species and analyze the regulation of its expression. We find that vasa protein accumulates in only a subset of cells(More)
Cortical granules are secretory vesicles formed in the eggs of most animals and are essential for the prevention of polyspermy in these organisms. We have studied the biogenesis of cortical granules in sea urchin oocytes by identifying cDNA clones that encode proteins targeted selectively to the cortical granules. These cDNA clones were identified by an(More)
Sexually reproducing metazoans establish a cell lineage during development that is ultimately dedicated to gamete production. Work in a variety of animals suggests that a group of conserved molecular determinants act in this germ line maintenance and function. The most universal of these genes are Vasa and Vasa-like DEAD-box RNA helicase genes. However,(More)
Trypsin-like activity is secreted from eggs of many species at fertilization, and this activity is believed to be critical for the block to polyspermy. Here we show that a cortical granule serine protease of sea urchins is the major and perhaps only protease family member important for fertilization. Zymography assays suggest that the cortical granules(More)
The regulation of yolk storage in oocytes and subsequent utilization in embryos is critical for embryogenesis. In sea urchins, the major yolk protein is made in the intestines, transported to the ovaries and accumulated in developing oocytes within membrane-bound vesicles comprising approximately 10% of the mass of an egg. Here, a non-yolk protein that(More)
Cortical granules of eggs contain a population of heterogeneous proteins that are sequestered selectively within the cortical granule during oogenesis and that participate in the block to polyspermy during the fertilization reaction. To begin to understand the targeting mechanism of proteins to this organelle, we have identified cDNA clones that encode(More)
The Spec1 and Spec2 genes of Strongylocentrotus purpuratus are closely associated with the differentiation of aboral ectoderm. To examine cis-regulatory elements involved in the spatial expression of the Spec genes, we fused the Escherichia coli lacZ gene containing a nuclear targeting signal to 5'flanking DNA plus 5' untranslated leader sequences from(More)