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H Cooke

Publications and source records attributed to H Cooke.

10 recordsLinked to original sources
PubMed1992

hnRNP A2/B1 binds specifically to single stranded vertebrate telomeric repeat TTAGGGn.

We have previously isolated a protein from mouse liver nuclei that specifically binds to single stranded (TTAGGG)n repeats. TTAGGG is the telomeric repeats of mammals and we therefore named the new protein single stranded telomere binding protein (sTBP). Further studies now identify sTBP as heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 on the basis of amino acid sequence determination and antibody reactivity. A2 and B1 form a major part of the protein component of hnRNP particles and are abundant nuclear proteins. Unexpectedly, A2/B1 has a high specificity for binding to the RNA equivalent of TTAGGG, UUAGGG, but under the same conditions does not appear to have a strong affinity for a number of other RNA species.

Amino Acid Sequence↗
PubMed1992

Lambda CM8, a human sequence with putative centromeric function, does not map to the centromere but is present in one to two copies at 9qter.

A DNA fragment isolated from a human genomic library, was reported to be present at all human centromeres and present at 16-32 copies per genome. Reintroduction of this DNA into mammalian cells as a concatenated phage clone gave rise to dicentric chromosomes which gave rise to a new, stable, chromosome. Taken together these observations could mean that this DNA is part of a native centromere. We have reexamined the location and copy number of this sequence and find it to be present at 1-2 copies per genome with a single site of in situ hybridisation at 9qter.

Blotting, Southern↗
PubMed1991

Functional reintroduction of human telomeres into mammalian cells.

Telomeric sequences of eukaryotes consist of short tandem repeats organized in arrays of variable length in which the guanine-rich strand runs 5'----3' toward the chromosomal end. The terminal repeats in yeast are the only elements necessary for telomere function in this organism. To test whether mammalian terminal repeats can function after reintroduction into a mammalian cell, a repeat-containing terminal fragment from a human chromosome was electroporated into a hamster-human hybrid cell line. In 6 of 27 independent transformants analyzed, the introduced sequences were found at the ends of chromosomes, based on all available criteria. Terminal restriction-fragment heterogeneity and the survival of these chromosomes demonstrate that these telomeres are functional. Cytogenetic evidence from one of these cell lines suggests that chromosome breakage with healing at the integration site is the mechanism responsible for the terminal location.

Animals↗
PubMed1991

Are patients' attitudes the cause of long waiting lists?

This paper studies the rate of non-attendance for both out-patient clinics and in-patient care. It relates this to the waiting times for both services. If all patients who did not attend clinics had informed us beforehand, thus enabling us to give their appointments to other patients, the out-patient waiting time could have been reduced from six months to one week. If a similar approach was taken with the in-patient waiting list, the waiting time could have been reduced from 15 months to nine months.

Appointments and Schedules↗
PubMed1990

The structure of a subterminal repeated sequence present on many human chromosomes.

All telomeres which have been studied consist of an array of simple G/C rich repeats. Human telomeres were shown to share sequence similarity with those of lower eukaryotes by cross-hybridization and human telomeric sequences have been cloned by complementation of telomere function in yeast. Analysis of human telomeric sequences cloned in this way is described here. The terminal part of the cloned human telomeric DNA consists of an array of simple repeats, principally of the sequence TTAGGG and derivatives. The very terminal part consists of yeast-type telomeric repeats which suggests that the human telomeric sequences have acted as a primer for the addition of additional telomeric repeats in the yeast. Subterminal sequences are shared between a number of clones and in situ data shows that these subterminal sequences are present at several different chromosomal ends. Related sequences are present at internal as well as telomeric positions. Differences in the hybridization patterns of subterminal sequences in somatic compared to germ-line tissues are described which indicate differential modification of these sequences during development.

Base Composition↗
PubMed1990

Effect of tamoxifen on regulation of viral replication and human immunodeficiency virus (HIV) long terminal repeat-directed transcription in cells chronically infected with HIV-1.

The protein kinase C (PKC) activator phorbol myristate acetate (PMA) was used to upregulate viral replication in a clone of promonocytic cells chronically infected with human immunodeficiency virus (HIV)-1. Induction of virus could be inhibited by the triphenylethylene anti-estrogen tamoxifen at concentrations that had minimal effects on cellular DNA synthetic responses and cell cycle kinetics. This effect correlated with tamoxifen's ability to block PMA-mediated enhancement of HIV-promoter-driven transactivation in cells of monocyte and CD4+ T-lymphocyte lineages. No interference with a primary infection was noted. Tamoxifen's mechanism of action may relate both to its capacity to inhibit PKC and to consensus sequences for gonadal steroid responsive elements in the HIV long terminal repeat, as it was able to partially inhibit another HIV activator, 5-azacytidine, which does not modulate PKC function. The finding that regulation of HIV in a model for low-level chronic or latent infection is amenable to a nonimmunosuppressive steroid antagonist may suggest approaches to pharmacologic intervention early in HIV infection.

Cell Cycle↗
PubMed1976

Repeated sequence specific to human males.

Restriction enzyme analysis and nucleic acid hybridisation show that there is a repeated sequence in human male DNA which is not present in human female DNA. This sequence is shown to constitute about 50% of the DNA in the Y chromosome and is a simple tandemly repeated DNA.

Base Sequence↗
PubMedDate not supplied

Using chromosome features in genome mapping.

Studies of the structure and function of chromosomal features and sequence elements have much to contribute to and gain from genome mapping. Abnormalities in chromosome banding associated with specific diseases have pinpointed regions of the genome for intensive analysis. An improved understanding of chromosome organization can facilitate gene identification and isolation, as well as enabling sophisticated genetic and vector systems for genome studies to be devised.

Animals↗