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Biomedical subjects

K M Higgins

Publications and source records attributed to K M Higgins.

23 records · Page 2Linked to original sources
PubMed1989

Cyclosporin A specifically inhibits function of nuclear proteins involved in T cell activation.

One action of cyclosporin A thought to be central to many of its immunosuppressive effects is its ability to inhibit the early events of T lymphocyte activation such as lymphokine gene transcription in response to signals initiated at the antigen receptor. Cyclosporin A was found to specifically inhibit the appearance of DNA binding activity of NF-AT, AP-3, and to a lesser extent NF-kappa B, nuclear proteins that appear to be important in the transcriptional activation of the genes for interleukin-2 and its receptor, as well as several other lymphokines. In addition, cyclosporin A abolished the ability of the NF-AT binding site to activate a linked promoter in transfected mitogen-stimulated T lymphocytes and in lymphocytes from transgenic mice. These results indicate that cyclosporin A either directly inhibits the function of nuclear proteins critical to T lymphocyte activation or inhibits the action of a more proximal member of the signal transmission cascade leading from the antigen receptor to the nucleus.

Base Sequence↗
PubMed1987

Purification of the T4 endonuclease V.

A new purification protocol has been developed for the rapid isolation to physical homogeneity of T4 endonuclease V. The enzyme was purified from an Escherichia coli strain which harbors a plasmid containing the T4 denV structural gene downstream of the lambda rightward promoter. The purification of the enzyme was monitored by pyrimidine dimer-specific nicking activity, Western blot analysis and silver or Coomassie Blue staining of SDS-polyacrylamide gels. Milligram quantities of the enzyme have been purified by the following procedure. After sonication of cells and removal of major cell debris, total protein and nucleic acids were passed over a single-stranded DNA agarose column. Endonuclease V was eluted at 650 mM KCl with a linear salt gradient yielding enzyme of approximately 20% purity and following dialysis, was applied to a chromatofocusing column. The enzyme elutes at pH 9.4 and is greater than 90% homogeneous at this step. The final purification step is CM-Sephadex chromatography which attains greater than 98% homogeneity.

Deoxyribonuclease (Pyrimidine Dimer)↗
PubMed1986

Expression of the bacteriophage T4 denV structural gene in Escherichia coli.

The expression of the T4 denV gene, which previously had been cloned in plasmid constructs downstream of the bacteriophage lambda hybrid promoter-operator oLpR, was analyzed under a variety of growth parameters. Expression of the denV gene product, endonuclease V, was confirmed in DNA repair-deficient Escherichia coli (uvrA recA) by Western blot analyses and by enhancements of resistance to UV irradiation.

Cloning, Molecular↗