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Biomedical subjects

D S Latchman

Publications and source records attributed to D S Latchman.

338 records · Page 19Linked to original sources
PubMed1984

The activation of cellular genes in transformed cells.

We have used differential cDNA cloning techniques to isolate a number of genes that are activated as a result of transformation by the DNA tumour virus Simian virus 40. From the nucleotide sequences of the cDNA clones we have been able to identify some of these genes. One of them derives from the major histocompatibility complex and contains a repetitive element that identifies a large number of RNAs present in pluripotential embryonic cells.

Animals↗
PubMed1984

Expression of the alpha-fetoprotein gene in pluripotent and committed cells.

We have studied the structure and expression of the alpha-fetoprotein gene in various cell types which differ in their capacity to synthesize alpha-fetoprotein. In all cells and tissues examined the levels of alpha-fetoprotein RNA found in the nucleus and cytoplasm were consistent with the hypothesis that alpha-fetoprotein expression is transcriptionally regulated. The alpha-fetoprotein gene was insensitive to deoxyribonuclease I in both undifferentiated embryonal carcinoma cells and in differentiated tissues which do not express alpha-fetoprotein, whereas in endoderm cells derived from the embryonal carcinoma cells and in alpha-fetoprotein-producing tissues the gene was sensitive to deoxyribonuclease I.

Animals↗
PubMed1983

A rapid method for analysis of the products of in vitro translation of messenger RNA.

A rapid and sensitive method for assaying the production of a specific protein during translation of messenger RNA is described. The method involves running the samples mixed with carrier protein in antibody-containing agarose and determining the radioactivity in the rocket-shaped immunoprecipitates which form. The radioactivity detected is shown to be qualitatively and quantitatively dependent on the amount of immunoreactive protein produced in translation and can thus be used as a measure of specific protein production. The ability of the method to rapidly analyze many samples in parallel is of particular use in screening large numbers of recombinant clones for the ability to bind a specific messenger RNA and affect its translation in vitro.

Albumins↗
PubMed1983

Transcripts regulated during normal embryonic development and oncogenic transformation share a repetitive element.

We have previously isolated cDNA clones homologous to mRNAs present at elevated levels in transformed mouse fibroblasts. Clones of Set 1 contain a dispersed repetitive element present thousands of times in the mouse genome. This repeat identifies in mouse embryos a large number of transcripts that are quantitatively regulated during development. At maximal expression these RNAs constitute between 1% and 3% of polyadenylated RNA. A pattern of Set 1-related transcripts very similar to that observed in midgestation embryos is found in pluripotential EC and EK cell lines, and the abundance of these RNAs decreases upon differentiation in vitro. However, the F9 line of EC cells, which has a more restricted developmental capacity, exhibits a much simpler pattern of transcripts containing the Set 1 repeat.

Age Factors↗
PubMedDate not supplied

Regulation of DNA virus transcription by cellular POU family transcription factors.

In the same way as other viral functions, the transcription of viral genes is frequently controlled by cellular regulatory proteins either acting alone or together with virally encoded factors. In this review, I discuss three examples of such regulation in different types of DNA viruses by different members of the POU family of transcription factors, all of which involve viruses which play a role in the aetiology of specific human diseases. These are the glial cell-specific transcription of JC virus which is controlled by the glial cell specific POU factor Tst-1; the regulation of human papillomavirus gene expression in the cervix by positively and negatively acting POU factors and the manner in which the balance between lytic or latent infection with HSV is controlled by positively and negatively acting POU factors which differ in their ability to interact with the virally encoded transactivator VP16. As well as being of interest in themselves, these processes may offer a therapeutic target for controlling the diseases caused by these very different viruses.

Amino Acid Sequence↗
PubMedDate not supplied

Pharmacological preconditioning of primary rat cardiac myocytes by FK506.

Pre-treatment with the immunosuppressant FK506 is shown to protect primary cardiocytes against a subsequent severe thermal or ischaemic stress. This effect is not observed with the related compounds cyclosporin A or rapamycin. It does not involve induction of the FK506 binding, heat inducible protein hsp56 or of the other heat shock proteins. In addition over-expression of hsp56 does not protect cardiac cells from severe stress in contrast to our previous results with hsp70 and hsp90. These results suggest the FK506 is acting via a novel mechanism to protect cardiac cells against cellular ischaemia which may not be related to its immunosuppressant action.

Alkaline Phosphatase↗
PubMedDate not supplied

The ability of heat stress and metabolic preconditioning to protect primary rat cardiac myocytes.

Primary rat cardiocytes were subjected to either thermal "preconditioning" for 30 min at 43 degrees C or 20 min metabolic "preconditioning" (10 mM deoxyglucose, 20 mM lactate, pH 6.5). Eighteen hours later cells were analysed either for hsp 70i expression or subjected to a subsequent lethal heat stress or simulated ischaemia (10 mM deoxyglucose, 20 mM lactate, 0.75 mM sodium dithionite, 12 mM potassium chloride, pH 6.5) for 2 hours and assessed for survival by trypan blue exclusion. Hsp 70i was induced over 100 fold by thermal "preconditioning" and 30 fold by metabolic "preconditioning" (p < 0.001, p < 0.05), hsp 90 was induced 2.71 fold and 2.24 fold (p < 0.001, p < 0.001) by thermal and metabolic "preconditioning" respectively, while hsp 60 was no induced by either treatment. Preconditioned cultures had improved survival against subsequent lethal heat stress or simulated ischaemia: Thermal "preconditioning" reduced death from 69.22% to 52.46% upon subsequent "lethal" heat stress and from 49.13% to 36.66% upon subsequent "lethal" simulated ischaemia. Metabolic "preconditioning" reduced cell death from 51.29% to 33.8% against subsequent "lethal" heat stress, and from 69.09% to 55.61% upon subsequent "lethal" simulated ischaemia. A second marker of cell death, the release of lactate dehydrogenase activity into the culture media, was reduced to 65% and 60% of control values for thermally preconditioned cells subjected to "lethal" heat or "lethal" simulated ischaemia respectively. Metabolically "preconditioned" cells demonstrated lactate dehydrogenase activity of 59% and 51% that of control values, when subjected to "lethal" heat or "lethal" simulated "ischaemia" respectively.

Animals↗
PubMedDate not supplied

In vivo myocardial gene transfer: optimization, evaluation and direct comparison of gene transfer vectors.

The purpose was to determine the relative efficiency, toxicity and duration of expression following gene delivery by intramyocardial injection of naked DNA, naked DNA complexed to cationic liposomes, naked DNA complexed to cationic liposomes with integrin-targetting peptide, recombinant (E1-/E3-) adenovirus, recombinant adeno-associated virus and recombinant (ICP27-) herpes simplex virus. All vectors incorporated a LacZ reporter driven by a promoter containing the hCMV-IE promoter/enhancer. Efficiency was scored by counting positive cells in five standard microscopic sections harvested from the left ventricular apex. Rabbit hearts (n = 100) were examined from 2 to 56 days after injection. Uncomplexed and complexed naked DNA were very inefficient with less than one positive cell visible per heart. The viral vectors all resulted in robust gene expression with adenovirus being the most efficient by at least one order of magnitude before 21 days. However, despite disparate titres, the efficiency beyond 21 days of adenovirus and adeno-associated virus were comparable. In contrast to adeno-associated virus, both adenovirus and herpes-simplex virus were associated with a marked inflammatory response. Despite reporter gene activity appearing only after 21 days, adeno-associated virus shows comparative promise as a myocardial gene delivery vector.

Adenoviridae↗
PubMedDate not supplied

Distinct responses of the herpes simplex virus and varicella zoster virus immediate early promoters to the cellular transcription factors Brn-3a and Brn-3b.

The related viruses herpes simplex virus (HSV) and varicella zoster virus (VZV) show distinct but related patterns of latent infection and reactivation in human sensory ganglia. The cellular POU family transcription factors Brn-3a and Brn-3b are expressed in sensory ganglia and bind to the TAATGARAT (R stands for purine) regulatory motifs in the immediate-early gene promoters of these viruses. We show that Brn-3a activates the full length HSV IE1 promoter whereas Brn-3b represses its activity. In contrast both Brn-3a and Brn-3b activate the full length VZV IE promoter. The response of the full length VZV promoter to Brn-3b is not observed with a minimal VZV immediate-early promoter lacking any TAATGARAT elements and cannot be restored by addition of either the upstream TAATGARAT-containing region of the HSV IE promoter or a VZV TAATGARAT-like element to this minimal promoter. The unique effect of Brn-3b on the full length VZV immediate early gene promoter may play a key role in the distinct pattern of latent infection and reactivation observed with this virus in vivo.

Cells, Cultured↗
PubMedDate not supplied

Activation of a Qa/Tla class I major histocompatibility antigen gene is a general feature of oncogenesis in the mouse.

A cDNA clone corresponding to a mRNA present at elevated levels in transformed fibroblasts encodes a Qa/Tla class I major histocompatibility complex (MHC) antigen. High levels of this mRNA are found in all tumour cells tested; the transcript can undergo alternative splicing; and a repetitive sequence within the transcription unit has the characteristics of a transposable element. The immunological implications of MHC gene activation in tumour cells are discussed.

Animals↗
PubMedDate not supplied

The class I major histocompatibility antigen gene activated in a line of SV40-transformed mouse cells is H-2Dd, not Qa/Tla.

We have previously described several complementary DNA clones isolated because they correspond to messenger RNAs present at higher levels in the simian virus 40 (SV40)-transformed BALB/c 3T3 cell line SV3T3 Cl38 than in the normal, parental BALB/c 3T3 line. One of these clones, pAG64, hybridizes to RNAs which, while present in BALB/c 3T3 cells, are 10-20-fold more abundant in SV3T3 Cl38 and are found at high levels in a wide variety of transformed cell lines. Nucleotide sequence analysis showed that pAG64 encodes a class I antigen of the major histocompatibility complex. To ascertain the identity of pAG64, we compared its sequence with the available sequences of d haplotype class I antigen genes [K locus, L locus, D locus and the Qa gene defined by genomic clone 27.1] and found that it showed multiple clustered differences from each of these sequences. We therefore concluded that it was not derived from the H-2Kd, H-2Ld or H-2Dd genes and thus must correspond to one of the other class I antigen genes, namely those of the Qa/Tla complex, although it was clearly not the Qa gene defined by the genomic clone 27.1. We now report subsequent findings which indicate that pAG64 in fact corresponds to the H-2Dd gene and not to a Qa/Tla gene.

Animals↗
PubMedDate not supplied

Herpes infection and AIDS.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Incidence of anti Hsp 90 and 70 antibodies in children with SLE, juvenile dermatomyositis and juvenile chronic arthritis.

OBJECTIVE: To determine the incidence of anti-hsp90 and 70 antibodies in children with SLE, juvenile dermatomyositis and juvenile chronic arthritis. METHODS: We utilized a previously described ELISA to detect the presence of antibodies to mammalian hsp90 and 70 in 33 children with SLE, 55 with juvenile chronic arthritis (JCA) and 11 with dermatomyositis. Sera from 19 children with non-autoimmune conditions served as controls. RESULTS: Antibodies reactive with hsp90 and/or 70 were detected in 35% of the children with SLE, and the numbers of children with SLE who have raised IgG anti-hsp90 antibodies (24%) is very similar to our adult onset cases, although the prevalence of IgM antibodies is much smaller. However, serum antibodies to hsp70 were as infrequent in children with SLE or JCA as in adults with SLE or RA, although IgG antibodies to hsp70 were detected in 50% of the synovial fluid of JCA patients. CONCLUSION: The incidence of antibodies to hsp90 in childhood-onset SLE resembles that described in adult onset disease suggesting that, despite clinical differences between the two, a subset of each may share a similar pathological mechanism of disease.

Adolescent↗