Jeffrey G. Williams

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The TTGA-binding factor is a transcriptional regulator activated by DIF, the chlorinated hexaphenone that induces prestalk cell differentiation in Dictyostelium. The same activity also functions as a repressor, controlling stalk cell differentiation. We show that the TTGA-binding factor is a STAT protein. Like the metazoan STATs, it functions via the(More)
There are cells scattered in the rear, prespore region of the Dictyostelium slug that share many of the properties of the prestalk cells and that are therefore called anterior-like cells (ALCs). By placing the gene encoding a cell surface protein under the control of an ALC-specific promoter and immunologically labeling the living cells, we analyze the(More)
We present evidence that Dictyostelium slug tip cells, the pstA cells, may arise by positional differentiation, but at a site remote from that which they will eventually occupy. When first detectable, the pstA cells form a peripheral ring surrounding the other prestalk cell subtype, the pstO cells, but subsequently move above the pstO cells to form the tip.(More)
  • Menzie D Chinn, Michael Leblanc, Olivier Coibion, Wong Cheung, Fred Joutz, Simon Van Norden +2 others
  • 2005
for very useful comments. This paper draws upon work conducted while the authors were staff members of the Council of Economic Advisers. None of the conclusions should be interpreted as representing the views of the U.S. Government or any other institutions the authors are affiliated with.The views expressed herein are those of the author(s) and do not(More)
The purpose of this study was to examine the effects of visual feedback on isokinetic maximum torque and reciprocal muscle group ratio of the knee extensors and flexors at a slow (60 degrees /set) and a fast (180 degrees /sec) speed of movement. The real-time gravity-corrected torque output, used as the visual feedback source, elicited a significant(More)
DNA double-strand breaks (DSBs) can be repaired by either homologous recombination (HR) or nonhomologous end-joining (NHEJ). In vertebrates, the first step in NHEJ is recruitment of the DNA-dependent protein kinase (DNA-PK) to DNA termini. DNA-PK consists of a catalytic subunit (DNA-PKcs) that is recruited to DNA ends by the Ku70/Ku80 heterodimer. Although(More)
Dictyostelium slugs expressing a dominant inhibitor of the cAMP-dependent protein kinase (PKA) selectively in prestalk cells are insensitive to the environmental signals that normally induce culmination (Harwood et al., 1992a). When such slugs do, eventually, attempt to culminate they are unable to activate stalk-specific gene expression and they become(More)
The mature fruiting body of Dictyostelium consists of stalk and spore cells but its construction, and the migration of the preceding slug stage, requires a number of specialized sub-types of prestalk cell whose nature and function are not well understood. The prototypic prestalk-specific gene, ecmA, is inducible by the polyketide DIF-1 in a monolayer assay(More)
Without the HAPPY map, the collaborators in the genome project would have found assembly to be extremely difficult, and the Dictyostelium genome sequence would perhaps have been left highly incomplete. With the HAPPY Map the YAC clones can be remapped and the original YAC skim strategy followed. In conclusion, this method has already made one community very(More)