Joan H. Pedersen-Lane

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Previous studies showed that thymidylate synthase (TS), as an RNA binding protein, regulates its own synthesis by impairing the translation of TS mRNA. In this report, we present evidence that p53 expression is affected in a similar manner by TS. For these studies, we used a TS-depleted human colon cancer HCT-C cell that had been transfected with either the(More)
Three group I introns of bacteriophage T4 have been compared with respect to their sequence and structural properties. The introns include the td intervening sequence, as well as the two newly described introns in the nrdB and sunY genes of T4. The T4 introns are very closely related, containing phylogenetically conserved sequence elements that allow them(More)
The nucleotide sequence of a 1,163-base-pair fragment that encodes the entire thyA gene of Escherichia coli K-12 was determined. The strategy involved sequence determination of both DNA strands by using overlapping deletions that had been generated in vitro from the two ends of the fragment with BAL-31 nuclease. The amino-terminal sequence of thymidylate(More)
Although the exact etiology of rheumatoid arthritis (RA) remains unknown, there is increasing evidence that reactive oxygen species and a pro-oxidant/antioxidant imbalance are an important part of the pathogenesis of joint tissue injury. Flow cytometry was used to evaluate the thiol status [surface-thiols and intracellular glutathione (iGSH)] of leukocytes(More)
A method is presented for expressing human thymidylate synthase (TS) to the extent of 25-30% of the protein in Escherichia coli. By this procedure, 200-400 mg of pure enzyme can be obtained from a 2-liter culture of cells. The key to the level of expression appears to be related to the conversion of purine bases in the third, fourth, and fifth codons of the(More)
In the present study, the effects of 10- or 100-nm silica oxide (SiO2) NPs on human peripheral blood mononuclear cells (PBMC) were examined. Cytotoxic effects and oxidative stress effects, including glutathione (GSH) depletion, the formation of protein radical species, and pro-inflammatory cytokine responses, were measured. PBMC exposed to 10-nm NP(More)
Escherichia coli thymidylate synthase (TS) is a dimeric protein containing identical subunits. When R126E, an inactive mutant of this enzyme, was incubated at room temperature with other inactive mutants of E. coli, TS enzyme activity gradually reappeared. The rate of activity restoration was dependent on the mutant employed. In the case of C146W, an active(More)
Of 97 nondirected T4 thymidylate synthase-defective (td) mutations, 27 were mapped to the intron of the split td gene. Clustering of these intron mutations defined two domains that are functional in splicing, each within approximately 220 residues of the respective splice sites. Two selected mutations, tdN57 and tdN47, fell within phylogenetically conserved(More)
The interrupted T4 phage td gene, which encodes thymidylate synthase, is the first known example of an intron-containing prokaryotic structural gene. Analysis of td-encoded transcripts provides evidence in favor of maturation at the RNA level. Northern blotting with T4 RNA and with region-specific probes revealed three classes of RNA: diffuse premessage(More)