John A. Crowell

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We have isolated 165 Caenorhabditis elegans mutants, representing 21 genes, that are resistant to inhibitors of cholinesterase (Ric mutants). Since mutations in 20 of the genes appear not to affect acetylcholine reception, we suggest that reduced acetylcholine release contributes to the Ric phenotype of most Ric mutants. Mutations in 15 of the genes lead to(More)
The recycling of synaptic vesicles requires the recovery of vesicle proteins and membrane. Members of the stonin protein family (Drosophila Stoned B, mammalian stonin 2) have been shown to link the synaptic vesicle protein synaptotagmin to the endocytic machinery. Here we characterize the unc-41 gene, which encodes the stonin ortholog in the nematode(More)
Electrophoretic and morphologic methods have been used to study the time course of [35S] methionine-labeled proteins accumulated in the incubation medium of rat fetal testes and seminiferous cords/tubules during their development. We have found that Sertoli cell-specific secretory proteins S70, S45 and S35 became progressively prominent as premeiotic,(More)
Cocultures of rat Sertoli-spermatogenic cells plated in a culture medium supplemented with 10% fetal bovine serum for 6-12 h and then maintained in serum free, hormone/growth factor-supplemented medium accumulated an acidic glycoprotein of molecular weight of 68,000 dalton (68 kD) and isoelectric point range of about 4.2-3.5. Anion exchange chromatography(More)
We have reconstituted specific RNA polymerase I transcription from three partially purified chromatographic fractions (termed A, B, and C). Here, we present the chromatographic scheme and the initial biochemical characterization of these fractions. The A fraction contained the RNA polymerase I transcription factor(s), which was necessary and sufficient to(More)
To estimate the potential of small doses of sarin (types I and II) and soman to cause delayed neuropathic effects, 400, 200, 61, and 0 micrograms/kg of sarin-I, 280, 140, 70, and 0 micrograms/kg of sarin-II, and 14.2, 7.1, 3.5, and 0 micrograms/kg of soman by gavage were compared with 510 mg/kg tri-o-cresyl phosphate (TOCP) in 14- to 18-month-old SPF white(More)
We extracted intermediate filament proteins (IFP) that were insoluble in in detergent from cultured rat Sertoli and peritubular cells after labeling with [35S] methionine and resolved them by two-dimensional polyacrylamide gel electrophoresis, autoradiography and Western blotting. We found that vimentin was the predominant IFP in both Sertoli and(More)
An approach combining two-dimensional gel electrophoresis and autoradiography was used to correlate patterns of secretory proteins in cultures of Sertoli and peritubular cells with those observed in the incubation medium from segments of seminiferous tubules. Sertoli cells in culture and in seminiferous tubules secreted three proteins designated S70 (Mr(More)
The cho-1 gene in Caenorhabditis elegans encodes a high-affinity plasma-membrane choline transporter believed to be rate limiting for acetylcholine (ACh) synthesis in cholinergic nerve terminals. We found that CHO-1 is expressed in most, but not all cholinergic neurons in C. elegans. cho-1 null mutants are viable and exhibit mild deficits in cholinergic(More)