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R Sen

Publications and source records attributed to R Sen.

At least 37 records · Page 2Linked to original sources
PubMed1989

A brain-specific transcription activator.

We have identified a DNA binding protein, named BETA, that interacts with the same (B) transcriptional regulatory sequence as the known transcription factor NF-kappa B. BETA is found only in gray matter throughout the brain, and not in a variety of other rat tissues. Two binding sites for BETA are present adjacent to the promoter of the rat proenkephalin gene. Transfection of primary brain cultures that express BETA, with a reporter gene driven by the SV40 promoter linked to BETA DNA binding sites, results in transcriptional activation. We infer that BETA is a brain-specific transcription activator.

Animals↗
PubMed1989

Alteration of a single nucleotide allows efficient binding of H2TF1/KBF1 to the immunoglobulin kappa enhancer B motif.

NF-kappa B (a protein present constitutively only in B cells) and H2TF1/KBF1 (a more ubiquitously distributed protein[s]) are two transcription factors that recognize very similar DNA sequences. However, the binding site associated with the kappa immunoglobulin gene enhancer (kappa B) is recognized predominantly by NF-kappa B. Using synthetically altered recognition sequences, we showed that the B-cell-specific NF-kappa B-binding site in the kappa enhancer can be converted to one that binds both NF-kappa B and the ubiquitous protein(s) H2TF1/KBF1 by substitution of a single nucleotide. Furthermore, transient transfection experiments suggested that NF-kappa B and H2TF1/KBF1 are functionally different even though their DNA recognition specificities are very similar.

Animals↗
PubMed1989

Bacillaemia and bone marrow involvement in leprosy.

Fifty patients (24 new and 26 receiving specific treatment) of leprosy were investigated to study the concentration and morphological index (MI) of the lepra bacilli in skin, peripheral blood and bone marrow. The organisms were detected in 28 cases on skin slit smear examination, in 38 cases on bone marrow examination and in 38 cases on examination of smears made from buffy coat of peripheral blood. Out of 22 cases negative for the bacilli on skin slit smears, 15 had the organisms either in buffy coat or bone marrow or both. Acid fast bacilli in peripheral blood and bone marrow with skin smear negativity were mainly observed in patients with paucibacillary type of the disease and in those who were receiving treatment. Examination of buffy coat and bone marrow for presence of lepra bacilli is suggested to establish the diagnosis in doubtful cases.

Bone Marrow↗
PubMed1988

The NF-kappa B-binding site mediates phorbol ester-inducible transcription in nonlymphoid cells.

The mouse immunoglobulin kappa light-chain enhancer can interact with at least three independent nuclear proteins. One of these proteins, NF-kappa B, is constitutively present only in nuclear extracts derived from B cells and plasma cells. A DNA-binding protein with the same sequence specificity (and therefore presumed to be NF-kappa B itself) can be induced in pre-B cells, T cells, and nonlymphoid cells by phorbol 12-acetate-13-myristate (PMA); however, it is not clear whether the induced factor can activate transcription in nonlymphoid cells as NF-kappa B does in B cells. In this paper we show that multimerization of a fragment of the mouse kappa enhancer that carried only the binding site for NF-kappa B behaved like a B-cell-specific regulatory element. Furthermore, this unit served to activate transcription in nonlymphoid cells after treatment with PMA (but not with cyclic AMP derivatives), and the kinetics of transcription activation correlated well with the kinetics of factor induction. Thus, the induced DNA-binding activity appeared to be functionally indistinguishable from that of NF-kappa B.

B-Lymphocytes↗
PubMed1988

Leukemoid reaction in erythema nodosum leprosum in a leprosy patient.

A case of lepromatous leprosy with erythema nodosum leprosum (ENL) presenting as a myeloid leukemoid reaction is reported. Very high leucocyte count with immaturity of the cells in myeloid series was present in peripheral blood. High leucocyte alkaline phosphatase score, absence of hepatosplenomegaly and transient nature of leukemoid reaction differentiated it from chronic myeloid leukemia and acute myeloblastic leukemia. The possible mechanisms of leukemoid reaction in ENL are discussed.

Adult↗
PubMed1987

In vitro transcription of immunoglobulin genes in a B-cell extract: effects of enhancer and promoter sequences.

Transfection experiments have led to the identification of three DNA sequences that are responsible for the tissue-specific expression of immunoglobulin genes. As a first step toward characterizing these regulatory phenomena at the biochemical level, we report the development of an in vitro transcription system from cells of the B lymphoid lineage. In these extracts, transcription of the MOPC41 kappa promoter is correctly initiated and dependent on the presence of an upstream sequence element located between -44 and -79 base pairs from the cap site. Second, although standard in vitro transcriptions are not affected by the presence or absence of enhancer sequences, we observed that the addition of polyethylene glycol led to a B-cell extract-specific suppression of transcription from a template that carries an immunoglobulin enhancer.

B-Lymphocytes↗
PubMed1986

Inducibility of kappa immunoglobulin enhancer-binding protein Nf-kappa B by a posttranslational mechanism.

NF-kappa B is a nuclear protein, found only in cells that transcribe immunoglobulin light chain genes, that interacts with a defined site in the kappa immunoglobulin enhancer. This protein can be induced in pre-B cells by stimulation with bacterial lipopolysaccharide (LPS). The induction involves a posttranslational activation, and the combined action of LPS and cycloheximide causes a superinduction. An active phorbol ester also induces this factor, and with kinetics more rapid than those for LPS stimulation. Phorbol-ester-mediated induction of NF-kappa B was observed in a T cell line (Jurkat) and a nonlymphoid cell line (HeLa), and is therefore not restricted to B-lymphoid cells. We interpret these results to indicate that factors that control transcription of specific genes in specific cells may be activated by posttranslational modification of precursor factors present more widely.

Anisomycin↗
PubMed1986

Multiple nuclear factors interact with the immunoglobulin enhancer sequences.

To characterize proteins that bind to the immunoglobulin (Ig) heavy chain and the kappa light chain enhancers, an electrophoretic mobility shift assay with end-labeled DNA fragments was used. Three binding proteins have been found. One is NF-A, a factor found in all tested cell types that binds to the octamer sequence found upstream of all Ig variable region gene segments and to the same octamer in the heavy chain enhancer. The second, also ubiquitous, protein binds to a sequence in both the heavy chain and the kappa enhancers that was previously shown to be protected from methylation in vivo. Other closely related sites do not compete for this binding, implying a restriction enzyme-like binding specificity. The third protein binds to a sequence in the kappa enhancer (and to an identical sequence in the SV40 enhancer) and is restricted in its occurrence to B cells.

Animals↗
PubMed1985

Characterization of mitochondrial monoamine oxidase of Ascaridia galli.

Oxidative deamination of various biogenic monoamines by Ascaridia galli monoamine oxidase (MAO) was blocked by different mammalian MAO inhibitors, namely, iproniazid, trans-PcP, nialamide and pargyline and the blockade was observed to be time as well as concentration dependent. The binding of inhibitors with chick ascarid MAO was of the irreversible type and the nature of the inhibition was competitive. Pargyline showed lowest I50 (8 microM) and Ki (12 microM) values. Chlorgyline and deprenyl at 100 microM concentration inhibited MAO by about 60 and 40% respectively, indicating the presence of both type A and type B MAO in A. galli.

Animals↗
PubMed1984

Ascaris lumbricoides and Ascaridia galli: biogenic amines in adults and developmental stages.

Ascaris lumbricoides var. hominis and Ascaridia galli contain 5-hydroxytryptamine, histamine, dopamine, and norepinephrine. The chick parasite showed lower levels of monoamines compared to human ascaris. Amine concentrations in females were higher than in males. In all specimens, 5-hydroxytryptamine was the highest while norepinephrine was found to be uniformly low. The female reproductive organ contained the maximum amount of dopamine while intestine was rich in histamine. A progressive increase in the concentrations of biogenic amines was noticed during development.

Animals↗
PubMed1983

Monoamine oxidase in adult Ascaridia galli.

Monoamine oxidase (MAO), catalysing oxidative deamination of biogenic monoamines, has been detected in adult Ascaridia galli. MAO was present in mitochondria and deaminated noradrenaline at the maximal rate, although serotonin, adrenaline, tyramine and dopamine were also degraded but more slowly. Of the organs studied, the body wall, female reproductive organ and intestine, the body wall (containing neuronal structures) showed highest MAO activity. Km value for chick ascarid mitochondrial MAO using tyramine as substrate was 1.66 X 10(-3) M and it was most active at 2.5 mM tyramine concentration, pH 7.5 and 40 degrees C. MAO of A. galli appeared to be thermolabile as nearly 80% of its activity was lost when the incubation temperature was increased 5 degrees above optimum.

Animals↗
PubMed1979

Composition of the aqueous phase of chromaffin granules.

Nuclear magnetic resonance spectroscopy has been used to determine the composition of the aqueous phase of bovine chromaffin granules. Relative concentrations of catecholamines (epinephrine plus norepinephrine), ATP and chromogranins have been measured from integrated intensities in the proton spectra using computer simulation techniques. Most or all of the catecholamines (97 +/- 8%) are present in the aqueous phase and contribute to the high resolution spectrum. The catecholamine:ATP molar ratio (4.41 +/- 0.45) determined by NMR is close to the value (4.45) derived from biochemical assay indicating that most or all of the ATP is present with catecholamine in the aqueous phase. Catecholamine:protein ratios show that approximately 45% of the soluble protein freed by lysis is not NMR visible. Intensity from this fraction does not appear under highly denaturing conditions (8 M urea) but reappears after hydrolysis. This behavior is similar to that of recently isolated soluble lipoprotein complexes. Variations in the NMR spectra associated with (1) different preparative procedures; (2) different suspension media, and (3) increasing osmolality are described. The fact that high concentrations of epinephrine and ATP (approximately 700 mM total) are dissolved in the aqueous phase implies that solution phase interactions at least partially ionic in nature are responsible for the low internal osmolality of chromaffin granules in vivo. Ordered phases containing a substantial fraction of the total catecholamine in an osmotically inactive form are not present.

Adenosine Triphosphate↗