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R J Grumont

Publications and source records attributed to R J Grumont.

25 records · Page 2Linked to original sources
PubMed1990

Murine c-rel transcription is rapidly induced in T-cells and fibroblasts by mitogenic agents and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate.

The c-rel protooncogene is here shown to be a member of the early response gene family. Expression induced by different agents is regulated by both transcriptional and posttranscriptional mechanisms. In quiescent fibroblasts, c-rel expression is maximally induced by serum or 12-O-tetradecanoylphorbol-13-acetate within 60 min and is superinduced in serum-stimulated fibroblasts by cycloheximide. In T-cells, although 12-O-tetradecanoylphorbol-13-acetate and concanavalin A both rapidly activate c-rel expression, the kinetics of induction mediated by these agents differs markedly. Nuclear run-on analysis demonstrates that induced c-rel expression is due primarily to increased transcription, and the rapid decrease in expression observed in serum- and 12-O-tetradecanoylphorbol-13-acetate-stimulated cells results from mRNA turnover. In the B-lymphoid lineage, c-rel is constitutively transcribed, with the differentiation stage-specific decrease in c-rel expression seen in plasmacytomas reflecting posttranscriptional regulation.

Animals↗
PubMed1989

The c-cbl proto-oncogene is preferentially expressed in thymus and testis tissue and encodes a nuclear protein.

Cas NS-1 is an acutely transforming murine retrovirus that induces early B-lineage lymphomas and occasional myeloid leukemias. The transforming sequence of this virus, v-cbl, shows no homology to known oncogenes but has some similarities to the yeast transcriptional factor GCN4. In this study we used a v-cbl probe to analyze mRNAs from a wide range of murine and human hemopoietic tumor cell lines and detected an 11-kilobase mRNA in all lineages. In normal mouse tissues the expression of c-cbl was highest in testis and thymus tissues, the predominant species in testis tissue being a 3.5-kilobase mRNA. The v-cbl oncogene was inserted into a bacterial expression vector to produce protein for the immunization of rabbits. Affinity-purified v-cbl antibodies identified abundant levels of p100gag-cbl in Cas NS-1-transformed fibroblasts and lower levels of a 135-kilodalton protein (p135c-cbl) in both normal and transformed cells. Subcellular fractionation showed that p100gag-cbl and p135c-cbl are both located in the nucleus and retained following 420 mM salt extraction. These results indicate that the translational product of a c-cbl is a 135-kilodalton nuclear protein.

Animals↗
PubMed1989

Structure of a mammalian c-rel protein deduced from the nucleotide sequence of murine cDNA clones.

The avian retrovirus, rev-T, which carries the viral oncogene v-rel, causes an acute leukemia in birds and transforms immature lymphoid cells in vitro. Although the role of c-rel in normal cells is unknown, homology with the Drosophila gene dorsal, which is involved in determining embryonic dorsal-ventral polarity, raises the possibility that c-rel in vertebrates may play a role in differentiation. As a step towards understanding its role in mammalian cells, we have characterized the coding domain of the 7.5 kb murine c-rel mRNA by isolating cDNA clones that span its entire coding domain and part of the 5' and 3' untranslated regions. The nucleotide sequence reported here indicates that murine c-rel encodes a 588 amino acid polypeptide with a predicted molecular weight of 66 kd. The murine protein shares homology with avian v-rel and dorsal over a 300 amino acid stretch within the amino terminus, while the carboxyl terminal regions of these proteins diverge completely. This suggests that the conserved domain of the rel related family of proteins performs a common function that is modulated by the carboxyl terminal domain.

Amino Acid Sequence↗
PubMed1986

Expression of Schistosoma japonicum antigens in Escherichia coli.

A cloned library of DNA complementary to the mRNA of adult Schistosoma japonicum has been prepared and expressed as fusion proteins with Escherichia coli beta-galactosidase. Colonies expressing the S. japonicum cDNA clones were screened both with antibodies from individuals with a history of schistosomiasis and with antibodies obtained from a rabbit immunized with whole adult worms. In both cases colonies were detected which bound antibody, although the frequency of antigen-positive clones was much higher with the rabbit antiserum than with human sera. In both cases the proportion of colonies reacting with antibodies was markedly lower than that published for equivalent screens of Plasmodium falciparum cDNA with sera from individuals with a history of falciparum malaria. Several major S. japonicum antigens were identified by the affinity purification of antibodies using immobilised fusion proteins produced during lytic growth of the recombinant bacteriophage.

Antibodies↗
PubMed1984

Characterization of isolates and clones of Leishmania by analysis of kinetoplast DNA.

The genetic characterization of pathogenic isolates of Leishmania was attempted by analysis of the molecular properties of kinetoplast DNA (kDNA) minicircles. Unit minicircle size is not conserved during speciation of Leishmania since the minicircles of strains and clones of L t major are smaller (700 bp) than those found in certain strains of L mexicana ssp (820 bp), L donovani (850 bp) or L t tropica (900 bp). Schizodeme analysis of minicircles reveals a high degree of sequence divergence in kDNA of Leishmania with the degree of microheterogeneity varying between species. This sequence divergence allows the discrimination of species, strains, and clones of Leishmania into schizodemes . Southern blot hybridization experiments reveal that at high stringency overall minicircle sequence homology is conserved among clones and strains of one species (L t major) but not between different species. This property of minicircle DNA permits the use of kDNA probes as a species-specific diagnostic test for the identification of unknown Leishmania isolates. The properties of kDNA from an L t tropica strain LRC- L32 (a " recidiva " organism) are so diverged from those of L t major strains as to support the classification [22, 23] of L t tropica and L t major as separate species of Leishmania rather than subspecies of L tropica.

Animals↗
PubMed1984

Identification of species, strains and clones of Leishmania by characterization of kinetoplast DNA minicircles.

Molecular analysis of kinetoplast deoxyribonucleic acid (kDNA) minicircles has permitted the genotypic characterization of pathogenic isolates of Leishmania species. The apparent size in agarose gels of unit-length minicircles released by EcoRI digestion of kDNA networks is not conserved during speciation in this genus since the minicircles of strains and clones of L. major are smaller (710 base pairs, bp) than those found in certain strains of L. mexicana subspecies (820 bp), L. donovani (825, 865 bp) or L. tropica (900, 930 bp). EcoRI-cut minicircles within any one species of Leishmania are heterogeneous in mobility during electrophoresis in acrylamide gels. Schizodeme analysis of minicircles reveals a high degree of sequence divergence in kDNA with the degree of microheterogeneity varying between species. This sequence divergence allows the discrimination of closely related clones and strains within a given species. Southern blot hybridization reveals that overall minicircle sequence homology is conserved among clones and strains of one species (L. major or L. tropica) but not between different species. This property of minicircle DNA permits the use of kDNA probes as a species-specific diagnostic test for the identification of Leishmania isolates. The analysis of kDNA from two L. tropica strains isolated at 14 year intervals from a patient with leishmaniasis recidivans has shown that the two strains are closely related, suggesting that the individual suffered the cutaneous disease as a result of a resurgence of the same parasite which caused the initial infection. The differences in the properties of kDNA from the L. tropica and L. major strains studied support the taxonomic separation of L. tropica and L. major into distinct species.

Animals↗