Cytosolic extracts of boar sperm contain a soluble phospholipase C (PLC) activity that induces Ca2+ release in sea-urchin (Lytechinus pictus) egg homogenates and an uncharacterized protein factor that causes Ca2+ oscillations when injected into mammalian eggs. In the present study we fractionated boar sperm extracts on three different FPLC chromatographic columns and found that the fractions th...

Jacques Loeb [4] developed procedures to make embryos from unfertilized sea urchin [5] eggs in 1899. Loeb called the procedures ?artificial parthenogenesis," and he introduced them and his results in ?On the Nature of the Process of Fertilization and the Artificial Production of Norma Larvae (Plutei) from the Unfertilized Eggs of the Sea Urchin? in an 1899 issue of The American Journal of Physi...

Gene network analysis requires computationally based models which represent the functional architecture of regulatory interactions, and which provide directly testable predictions. The type of model that is useful is constrained by the particular features of developmentally active cis-regulatory systems. These systems function by processing diverse regulatory inputs, generating novel regulatory...

A transcription factor that regulates skeleton formation in sea urchin embryos has evolved a new domain that is essential for this process.

Regulatory networks of transcription factors and signaling molecules lie at the heart of development. Their architecture implements logic functions whose execution propels cells from one regulatory state to the next, thus driving development forward. As an example of a subcircuit that translates transcriptional input into developmental output, we consider a particularly simple case, the regulat...

Recent studies have investigated the dendritic actin cytoskeleton of the cell edge's lamellipodial (LP) region by experimentally decreasing the activity of the actin filament nucleator and branch former, the Arp2/3 complex. Here we extend these studies via pharmacological inhibition of the Arp2/3 complex in sea urchin coelomocytes, cells that possess an unusually broad LP region and display cor...

For hundreds of years, biologists have studied accessible organisms such as garden peas, sea urchins collected at low tide, newt eggs, and flies circling rotten fruit. These organisms help us to understand the world around us, attracting and inspiring each new generation of biologists with the promise of mystery and discovery. Time and time again, what we learn from such simple organisms has em...

' Watson, J. D., and F. H. C. Crick, in Viruses, Cold Spring Harbor Symposia on Quantitative Biology, vol. 18 (1953), p. 123. 6Koch, A. L., and C. Miller, J. Theoret. Biol., 8, 71 (1964). 7 Fong, P., these PROCEEDINGS, 52, 641 (1964). 8 Dounce, A. L., J. Theoret. Biol., 2, 152 (1962). 9 Cavalieri, L. F., and B. J. Rosenberg, in Progress in Nucleic Acid Research, ed. J. N. Davidson and W. E. Coh...

Biochemical fractionation of axonemal microtubules yields the protofilament ribbon (pf-ribbon), an insoluble structure of 3-4 longitudinal protofilaments composed primarily of alpha/beta tubulin, tektins A, B and C, and two previously uncharacterized polypeptides of 77 kDa and 83 kDa. We have isolated the 77/83 kDa polypeptides (termed Sp77 and Sp83) from sperm flagella of the sea urchin Strong...