Biomedical subjects

N M Williamson

Publications and source records attributed to N M Williamson.

5 recordsLinked to original sources

PubMed1997

High-throughput RT-PCR analysis of multiple transcripts using a microplate RNA isolation procedure.

We have developed a high-throughput, multiplex reverse transcription PCR (RTPCR) assay that is suitable for the analysis of medium-to low-copy cellular RNA transcripts from small numbers of cells (10(4)). High throughput was attained by utilizing microplate-based RNA extraction and RTPCR protocols, followed by PCR product visualization of a multiwelled agarose gel, stained with SYBR Green I dye. The transcriptional assay was unaffected by solvents (dimethyl sulfoxide and methanol) routinely used in high-throughput drug screens at concentrations required for compound solubilization. Furthermore, it has been used successfully for the investigation of differential mRNA expression levels of tumor necrosis factor alpha (TNF-alpha) and Interleukin-1 beta (IL-1 beta) in lipopolysaccharide (LPS)-stimulated THP-1 cells (a human monocytic cell line) and the identification of specific IL-1 beta transcriptional inhibitors.

Benzothiazoles↗

PubMed1989

Cellular targets for transformation by the adenovirus E1A proteins.

Three cellular proteins, including species of 300,000 daltons and 107,000 daltons as well as p105-RB, the product of the retinoblastoma susceptibility gene, stably interact with the adenovirus E1A proteins. To help determine the functional basis of these interactions, the regions of E1A that participate in these interactions were mapped using a series of deletion mutants. The 300,000 dalton and the 107,000 dalton proteins interacted with sequences within amino acids 1 to 76 and 121 to 127, respectively. Interaction with the third cellular protein, p105-RB, required the presence of sequences from two noncontiguous regions of the E1A polypeptide chain, amino acids 30 to 60 and 121 to 127. The regions of E1A that are required for these interactions coincided precisely with the regions of E1A that are required for its transforming function. These results suggest that the interactions with these cellular proteins are fundamental to the transforming activity of E1A.

Adenovirus Early Proteins↗

PubMed1985

Molecular cloning and in vitro expression of a cDNA clone for human cellular tumor antigen p53.

Three clones for the human tumor antigen p53 were isolated from a cDNA library prepared from A431 cells. One of these clones, pR4-2, contains the entire coding region for human p53. This clone directs the synthesis of a polypeptide with the correct molecular weight and immunological epitopes of an authentic p53 molecule in an in vitro transcription-translation reaction. Although the pR4-2 clone contains the coding region for p53, it is not a full-length copy of the human p53 mRNA. Northern analysis showed that the p53 mRNA is approximately 2,500 nucleotides long, whereas the pR4-2 insert is only 1,760 base pairs in length. Analysis of the DNA sequence of this clone suggests that the human p53 polypeptide has 393 amino acids. We compared the predicted amino acid sequence of the pR4-2 clone with similar clones for the mouse p53 and found long regions of amino acid homology between these two molecules.

Amino Acid Sequence↗

PubMed1983

Evidence for central alpha-adrenergic transmission in a cardio-inhibitory response from the rabbit hypothalamus.

The heart rate of the anaesthetized rabbit was slowed by electrical stimulation of the hypothalamus with 7-9 sec trains of 250-330 microA pulses, duration 1 msec, frequency 60 Hz. This vagally-mediated cardio-decelerator response was attenuated in a dose-dependent manner after intravenous administration of phenoxybenzamine (0.01-5 mg/kg), phentolamine (0.01-3 mg/kg) or yohimbine (0.1-5 mg/kg). The attenuation of the cardio-decelerator response was not due to any vagolytic action of these drugs nor to block of the baroreceptor reflex, but appeared to be due to a central block of pathways descending from the hypothalamus. Propranolol, haloperidol, pimozide and spiperone did not show this central blocking action except in very large doses when there was evidence of some alpha-adrenoceptor blockade.

Adrenergic alpha-Antagonists↗

PubMed1981

Monoclonal antibodies specific for simian virus 40 tumor antigens.

Thirty hybridomas that secrete immunoglobulins against the simian virus 40 tumor antigens were isolated and cloned. Of these, 28 produced antibodies which bound to simian virus 40 large-T, and 2 produced antibodies which bound to the host 53,000-dalton protein. As in previous work, large-T antigen was found to have at least one determinant that it shared with small-t antigen and to have a minimum of six unique determinants. Several of the monoclonal antibodies from the L series hybridomas recognized determinants that were present on a subset of the large-T antigen from simian virus 40-transformed mouse cells. These monoclonal antibodies should be useful in studies of the structure and function of the simian virus 40 tumor antigens.

Antibodies, Monoclonal↗