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Biomedical subjects

D J Hall

Publications and source records attributed to D J Hall.

At least 19 recordsLinked to original sources
PubMed1992

Isolation of a novel cDNA encoding a zinc-finger protein that binds to two sites within the c-myc promoter.

The ME1a1 and ME1a2 elements are cis-acting DNA sequences that exist at positions -46 and -85, respectively, within the P2 promoter of the c-myc gene. These elements are required for optimal transcription initiation from P2. The proteins that bind to these elements are identical or very similar. Here we have isolated a cDNA clone that encodes the carboxy-terminal 494 amino acids of the human ME1a1/ME1a2 factor. This factor is referred to as "ZF87" (zinc-finger protein, 87 kilodaltons). ZF87 specifically binds the ME1a1 element with higher affinity than the ME1a2 element. Western blot analysis indicates that the full-length protein has a relative molecular mass of approximately 87,000 daltons, and Northern blot analysis shows that it is encoded by a 5-kb transcript. ZF87 contains six zinc-finger domains, of the Cys2-His2 type, at the carboxy terminus of the protein. The protein also contains extended tracts of polyalanine.

Amino Acid Sequence↗
PubMed1992

Wild-type murine p53 represses transcription from the murine c-myc promoter in a human glial cell line.

Here we analyzed the effect of the suppressor proto-oncogene p53 on transcription from the P2 promoter of the murine c-myc gene. c-myc promoter constructs were coupled to the chloramphenicol acetyl-transferase (CAT) gene and were transiently transfected into a human glial cell along with plasmids overexpressing wild-type or mutant p53. It was found that significant repression of c-myc transcription took place following cotransfection with wild-type but not mutant p53. However wild-type p53 did not suppress transcription from the SV40 early promoter or from the MHC promoter. Promoter-CAT constructs containing only the ME1a2 or E2F elements, from the P2 promoter, were repressed by p53, indicating that p53 may exert its effect at these two sites within the P2 promoter. Finally, when the SV40 T antigen and wild-type p53 were expressed together in glial cells the repressive effect of p53 was abolished.

Animals↗
PubMed1992

Proteolytic processing of the cardioviral P2 region: primary 2A/2B cleavage in clone-derived precursors.

The primary 2A/2B cleavage within cardiovirus polyprotein was examined by construction of cDNA plasmids which linked fragments from the P2 region of encephalomyocarditis virus (EMCV) and Mengovirus genomes to the EMCV 5' nontranslated region. When RNA transcripts from these clones were tested in reticulocyte extracts, the synthesized proteins were cotranslationally processed at the 2A/2B site. No viral segments outside of the P2 region were required for this activity. Engineered deletions which removed the amino-terminal two-thirds of protein 2A or the carboxyl half of protein 2B had no effect on this scission, nor did insertions into a Ser-Ala-Phe sequence (SAF) within 2B, which is conserved in most cardio- and aphthoviruses. In contrast, mutations which disrupted a conserved Asn-Pro-Gly-Pro (NPGP) sequence abolished primary scission. Precursors thus inactivated were unable to serve as substrate when simultaneously expressed with active (wild-type) 2AB sequences. Microsequencing placed the EMCV primary cleavage site between the Gly/Pro pair within the NPGP sequence. It was also determined that endogenous viral protease 3C is the previously unidentified agent responsible for cardiovirus 1D/2A scission, a cleavage that is part of the primary processing reaction in poliovirus.

Amino Acid Sequence↗
PubMed1992

The Nithsdale schizophrenia surveys. X: Obstetric complications, family history and abnormal movements.

Obstetric histories of 54 schizophrenic patients and 114 siblings were obtained from their mothers and scored using the Obstetric Complications Scale. There were no statistically significant difference in the proportion of schizophrenic patients (35%) and siblings (29%) who had at least one definite obstetric complication. There was no evidence that schizophrenic patients with a history of obstetric complications were less likely to have a first-degree relative with a history of psychiatric illness leading to in-patient care. Schizophrenic patients with a history of obstetric complications were more likely to have drug-induced Parkinsonism. There was a trend for tardive dyskinesia to be more common in those schizophrenic patients with no obstetric complications but a family history of schizophrenia.

Adult↗
PubMed1992

The metabolism of imiloxan hydrochloride in healthy male volunteers.

1. The metabolism of imiloxan hydrochloride [(+-)-2-(1-ethyl-2-imidazoyl)methyl-1,4-benzodioxane hydrochloride], an alpha 2-adrenoceptor antagonist, was studied in four male volunteers given a 500 mg oral dose containing 0.48 MBq of the 14C-labelled material. Compound-related radioactivity was rapidly excreted chiefly in the urine within 24 h of dosing. 2. Metabolites derived by initial oxidation on either or both the benzodioxane and imidazoyl moieties followed by glucuronic acid and sulphate conjugation, and an N-glucuronide of imiloxan were tentatively identified in urine. 3. The major urinary metabolites, comprising some 37-41% of the dose, appeared to be +-2-(1-ethyl-2-imidazoyl)methyl-1,4-benzodioxane-6/7-sulphonic acid (19% of dose), [+-2-(1-ethyl-2-imidazoyl)methyl-1,4-benzodioxane- 6/7-ylium D-glucopyranoside]uronate (10-14% of dose), and a glucuronide conjugate of +-2-(1-ethyl-2-imidazoyl-4/5-hydroxy)methyl-1,4-benzodioxane (8% of dose).

Adrenergic alpha-Antagonists↗
PubMed1992

Three distinct elements within the murine c-myc promoter are required for transcription.

We have undertaken a detailed analysis of the cis-acting elements that are required for optimal transcription initiation from P2, the major promoter of the murine c-myc gene. We find that three elements contribute to promoter strength, termed ME1a2, E2F and ME1a1 at positions -85, -64 and -46 respectively (relative to P2). Individually the elements are weak, but combined they contribute to full promoter activity, all acting in a positive fashion. The E2F element is the site at which the SV40 large T antigen transactivates the c-myc promoter. However, transactivation requires the presence of the ME1a2 or ME1a1 elements in addition to E2F. By a number of criteria it appears that the ME1a2 and ME1a1 elements bind the same or a very closely related protein (monomer Mr 94,000). It was found that Hela cells contain a novel factor that is capable of binding to the ME1a1 and ME1a2 elements but only in the presence of the protein-dissociating agents deoxycholate or formamide. Finally, the E2F factor binds DNA both as a monomer and as a multiprotein complex; the latter is cell type specific. Both types of bound E2F factor form less stable protein-DNA complexes than the ME1a2/ME1a1 factor.

3T3 Cells↗
PubMed1991

Tyrosine phosphorylation of a yeast 40 kDa protein occurs in response to mating pheromone.

Tyrosine phosphorylation of proteins in the yeast Saccharomyces cerevisiae has been examined following exposure to the mating pheromone alpha-factor. When a cells are treated with alpha-factor a protein of approximately 40 kDa molecular weight is tyrosine phosphorylated. This tyrosine phosphorylation response requires an intact signal transduction pathway, is not restricted to a short interval of the cell division cycle, and requires protein synthesis for its maximal accumulation. Mating competent fus3 deletion strains fail to elaborate the phosphotyrosine response. The possibility that FUS3 encodes the 40 kDa protein is discussed.

Blotting, Western↗
PubMed1991

Analysis of the c-myc P2 promoter.

The cis-acting elements governing transcription from the murine c-myc P2 promoter have not been well defined. To gain a better understanding of the nature of the protein-DNA interactions that take place on the P2 promoter, protein binding assays were performed. The ME1a2 and E2F factors appear to be the predominant proteins bound to a region spanning positions -140 to -24 relative to the P2 transcription start site. By a number of criteria, these factors appear to be distinct. When c-myc promoter sequences were coupled to the chloramphenicol acetyltransferase gene (CAT) and transiently transfected into tissue culture cells it was found that optimal transcription from P2 was heavily dependent on the ME1a2 element.

Animals↗
PubMed1979

Congenital abnormalities and Perthes' disease. Clinical evidence that children with Perthes' disease may have a major congenital defect.

This paper reports a high incidence of minor congenital anomalies in boys and girls with Perthes' disease compared with that in a control population. There is a similarity of the incidence of minor anomalies in the children with Perthes' disease to that in babies with a single major congenital defect. Multiple major defects were more numerous and more severe than in the control children. It is speculated that there may be a congenital abnormality affecting skeletal development which in some way makes the hip susceptible to Perthes' disease at a later date.

Abnormalities, Multiple↗
PubMed1979

Multidisciplinary management of Crouzon syndrome.

The comprehensive management of Crouzon syndrome in a 14-year-old girl has been presented. Because of the complexity of the facial and associated problems, a multidisciplinary approach is necessary to provide maximum functional and esthetic results; however, with such a cooperative interdisciplinary effort, the improvement and benefits derived for these patients are rewarding to all concerned.

Adolescent↗
PubMed1979

A new technique for vulvar skin grafting.

A new and easy technique for handling and applying a split-thickness skin graft to the vulva is described. The use of petrolatum gauze backing and application with the skin stapler, as well as postoperative management, are discussed.

Female↗
PubMed1979

Kaposi's sarcoma of the vulva: a case report and brief review.

A report of a case of Kaposi's sarcoma of the vulva is presented. A complete response of the tumor was obtained after 1 treatment cycle using a triple-drug chemotherapy regimen of actinomycin D, vincristine, and 5-(3,3-dimethyl-1-trazeno)imidazole-4-carboxamide (DTIC). Death occurred due to severe erythema multiforme, which was indirectly related to a complication of the chemotherapy.

Antineoplastic Agents↗
PubMed1978

Critical point drying for scanning electron microscopy: a semi-automatic method of preparing biological specimens.

Slow, controlled, rates of critical point bomb heating and of gas venting have been shown to improve the preservation of biological specimens in critical point drying. A procedure that represents a balance between avoidance of specimen damage and speed of operation has been developed for use with CO2 as the transitional fluid. Bomb heating is automated and controlled electronically, and manual venting of the gaseous CO2 is monitored using a gas flow meter.

Carbon Dioxide↗