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V Stolc

Publications and source records attributed to V Stolc.

At least 19 recordsLinked to original sources
PubMed1998

Rpp2, an essential protein subunit of nuclear RNase P, is required for processing of precursor tRNAs and 35S precursor rRNA in Saccharomyces cerevisiae.

RPP2, an essential gene that encodes a 15.8-kDa protein subunit of nuclear RNase P, has been identified in the genome of Saccharomyces cerevisiae. Rpp2 was detected by sequence similarity with a human protein, Rpp20, which copurifies with human RNase P. Epitope-tagged Rpp2 can be found in association with both RNase P and RNase mitochondrial RNA processing in immunoprecipitates from crude extracts of cells. Depletion of Rpp2 protein in vivo causes accumulation of precursor tRNAs with unprocessed introns and 5' and 3' termini, and leads to defects in the processing of the 35S precursor rRNA. Rpp2-depleted cells are defective in processing of the 5.8S rRNA. Rpp2 immunoprecipitates cleave both yeast precursor tRNAs and precursor rRNAs accurately at the expected sites and contain the Rpp1 protein orthologue of the human scleroderma autoimmune antigen, Rpp30. These results demonstrate that Rpp2 is a protein subunit of nuclear RNase P that is functionally conserved in eukaryotes from yeast to humans.

Endoribonucleases↗
PubMed1997

Rpp1, an essential protein subunit of nuclear RNase P required for processing of precursor tRNA and 35S precursor rRNA in Saccharomyces cerevisiae.

The gene for an essential protein subunit of nuclear RNase P from Saccharomyces cerevisiae has been cloned. The gene for this protein, RPP1, was identified by virtue of its homology with a human scleroderma autoimmune antigen, Rpp30, which copurifies with human RNase P. Epitope-tagged Rpp1 can be found in association with both RNase P RNA and a related endoribonuclease, RNase MRP RNA, in immunoprecipitates from crude extracts of cells. Depletion of Rpp1 in vivo leads to the accumulation of precursor tRNAs with unprocessed 5' and 3' termini and reveals rRNA processing defects that have not been described previously for proteins associated with RNase P or RNase MRP. Immunoprecipitated complexes cleave both yeast precursor tRNAs and precursor rRNAs.

Amino Acid Sequence↗
PubMed1997

Rpp1, an essential protein subunit of nuclear RNase P required for processing of precursor tRNA and 35S precursor rRNA in Saccharomyces cerevisiae.

The gene for an essential protein subunit of nuclear RNase P from Saccharomyces cerevisiae has been cloned. The gene for this protein, RPP1, was identified by virtue of its homology with a human scleroderma autoimmune antigen, Rpp30, which copurifies with human RNase P. Epitope-tagged Rpp1 can be found in association with both RNase P RNA and a related endoribonuclease, RNase MRP RNA, in immunoprecipitates from crude extracts of cells. Depletion of Rpp1 in vivo leads to the accumulation of precursor tRNAs with unprocessed 5' and 3' termini and reveals rRNA processing defects that have not been described previously for proteins associated with RNase P or RNase MRP. Immunoprecipitated complexes cleave both yeast precursor tRNAs and precursor rRNAs.

Amino Acid Sequence↗
PubMed1997

Characterization of a promoter within the first intron of the human CD4 gene.

The CD4 molecule is subject to complex regulation during T cell differentiation and activation. The elements regulating CD4 gene expression have only partially been defined. In this report, we identified a promoter element located in the first intron of the CD4 gene. This promoter preferentially functions in T cell lines and is preferentially active in CD4+, CD8+ cells. These findings are similar to other systems in which multiple promoters define tissue- and developmental-specific patterns of expression. Through a series of deletions, electrophoretic mobility shift assays and exonuclease III protection assays, we localized the basal promoter element to a 32-bp fragment. This element lacks potential binding domains for myb and ets, both of which have previously been shown to be involved in the function of the 5' murine and human CD4 promoter, and this suggests the presence of a novel, T-cell-specific transcription factor. These results also suggest that the CD4 expression requires the use of multiple regulatory elements located throughout the CD4 gene.

Base Sequence↗
PubMed1997

Characterization of two scleroderma autoimmune antigens that copurify with human ribonuclease P.

Human RNase P has been purified more than 2000-fold from HeLa cells. In addition to the RNA component, H1 RNA, polypeptides of molecular masses 14, 20, 25, 30, 38, and 40 kDa copurify with the enzyme activity. Sera from two different patients with the autoimmune disease scleroderma were used to immunodeplete human RNase P activity. These same sera cross-reacted on immunoblots with two of the copurifying polypeptides, p30 and p38, whereas an autoimmune serum that does not immunodeplete RNase P activity did not react with these proteins. Peptide fragments derived from purified p30 and p38 facilitated the molecular cloning and sequencing of cDNAs coding for these two polypeptides, which are now designated as Rpp30 and Rpp38, respectively. RPP38 cDNA encodes a polypeptide that may be identical to a previously identified antigen of approximately 40 kDa, which is immunoprecipitated by Th and To autoimmune antisera, and that has been implicated as a protein subunit of human RNase P by virtue of its ability to bind to H1 RNA in vitro. The second autoimmune antigen, Rpp30, as such, has not been described previously.

Amino Acid Sequence↗
PubMed1991

Down's syndrome and mixed acute leukemia in infants.

The routine use of panels of monoclonal antibodies has been complementary to the French-American-British (FAB) leukemia classification, and has unmasked the occurrence of mixed acute leukemia (myeloid-lymphoid). It is widely accepted that children with Down's syndrome (DS) have a high incidence of acute leukemia. There is an extensive body of literature emphasizing the cytogenetic findings in these children. However, information as to the immunophenotype is often limited to the lymphoid surface determinants. The authors report two children with DS whose leukemic blasts were studied with a panel of 17 monoclonal antibodies (myeloid, lymphoid, and megakaryocytic) by flow cytometric examination and were classified as biphenotypic acute leukemia. The blast population coexpressed myeloid and T-cell surface markers. The lymphoid origin was ruled out on the basis of negative terminal deoxynucleotidyl transferase and molecular analysis demonstrating germline configuration for the JH and beta TCR genes.

Antibodies, Monoclonal↗
PubMed1991

Detection of rearrangement of immunoglobulin heavy chain and T-cell receptor beta chain in leukemic cells by restricted polymerase chain reaction.

Rearrangement of the immunoglobulin heavy chain and of the T-cell receptor beta subunit was analyzed by using restricted polymerase chain reaction (PCR). To differentiate between the germline configuration and the rearranged genome in a DNA sample extracted from lymphocytes, we compared the ratio of the amplified products. The intensity of amplification of the intron region (JHF) upstream of the first joining region was compared to the intensity of joining region 6 of the immunoglobulin heavy chain. The number of the amplification cycles in the PCR was designated in such a way that the ratio of JHF/JH6 was less than one in the rearranged configuration. As the concentration of clonal B-lymphocytes with the rearranged genome in the sample increased the amplification of the JHF intron proportionally decreased. We used the same approach for the two constant regions of the T-cell receptor beta chain. As one of the intron regions of the constant sequence became depleted by rearrangement so the amplification of the particular region decreased. Therefore, the absence or decreased concentration of a particular product of amplification indicated deletion and thus rearrangement of the genome in the leukemic B- or T-lymphocytes. The threshold of detection of cells with the rearranged genome on a photograph of agarose gel loaded with the particular amplified regions and staining with the ethidium bromide is less than 10% by densitometric tracing and 25-50% by visual evaluation. This novel approach allows the detection of the rearranged DNA sequences in a 2 day span. Hence, it can serve as a diagnostic tool for the identification of clonal expansion of lymphocytes in acute leukemias and lymphomas in particular and for the detection of deleted genomic regions in general.

Amino Acid Sequence↗
PubMed1991

Polymorphism of cyclic 3',5'-adenosine monophosphate stimulation in rat erythrocytes.

Significant differences were found in the cyclic 3',5'-adenosine monophosphate (cAMP) levels in (-)-isoproterenol-stimulated rat erythrocytes. The BN strain had the highest level (13.1 +/- 1.29 pmol cAMP/10 mg Hb) and the LEW strain had the lowest cAMP level (3.29 +/- 1.76 pmol cAMP/10 mg Hb) in the erythrocytes. The high levels were inherited in three intercrosses in a dominant fashion. The results of the backcross breeding suggested diallelic inheritance. However, the polygenic effect was not ruled out.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Immunophenotyping in the classification of acute leukemia in adults. Interpretation of multiple lineage reactivity.

Fifty-nine adult patients with acute leukemia were classified using a combination of the French-American-British (FAB) criteria and characterization by immunophenotyping using flow cytometric study. The authors identified 51 patients with acute myeloblastic leukemia and eight with acute lymphoblastic leukemia. This procedure permitted lineage assignment in leukemias that otherwise might have been unclassifiable. In addition, the authors demonstrated that the leukemic blasts of 29% of patients with myeloblastic disease exhibited one or more T-cell antigens on their surface. The use of immunophenotyping has greatly enhanced the authors' ability to correctly identify the lineage of acute leukemias. The data, however, must be interpreted with caution with respect to diagnosing acute mixed lineage leukemias and must be integrated with the morphologic and cytochemical evaluation of traditional classification schemes. The possible significance of T-cell markers in myeloblastic leukemia is discussed.

Adult↗
PubMed1989

Microgranular promyelocytic leukemia: a multiparameter examination.

Six cases of microgranular variant acute promyelocytic leukemia (M3v) were studied by use of a multiparameter approach including morphology, cytochemistry, flow cytochemistry, flow cytometry, cytogenetics, and gene rearrangement. Three of six cases demonstrated both myeloid and monocytoid associated surface markers by flow cytometry. One of six cases had strong alpha-naphthyl-butyrate esterase (alpha-NBE) activity in addition to myeloperoxidase activity. There was no correlation between percentage of positive monocytoid surface markers and intensity of cytoplasmic alpha-NBE activity. Four of six cases also had a T-cell-associated surface antigen. Further studies indicated that the T-cell markers appeared to be on the promyelocytes and that the T-B receptor gene was not rearranged. Similarly, cytogenetics studies indicated only one clonal abnormality t(15q+; 17q-). Whether these cases represent true "lineage infidelity" remains to be answered. Future important studies are needed on normal hematopoietic progenitor cells at early stages of development and childhood to study lineage-specific characteristics and to determine whether co-expression normally exists during early development.

Adult↗
PubMed1989

Regulation of total leukocyte, neutrophil and lymphocyte concentrations in human blood by major effectors.

Commingling analysis of total leukocyte, neutrophil and lymphocyte concentrations in human blood suggested the effect of major regulatory factors affecting each type of white blood cells. Our results showed two distributions for the total leukocyte and lymphocyte concentrations. The values of the low and high phenotypes were 5.8 and 8.4 x 10(9)/l of total leukocytes and 2.0 and 4.6 x 10(9)/l of total lymphocytes. On the other hand, the neutrophil concentration in blood is probably regulated by equally penetrant factors. The means of the three phenotypes were 2.6, 4.2 and 6.5 x 10(9)/l. The evidence of two or three phenotypes, although consistent with the effect of a single-factor hypothesis (genetic or environmental), must be confirmed by segregation analysis of families.

Adolescent↗
PubMed1987

A polymorphic variant of the lactate dehydrogenase B subunit in the rat.

A new electrophoretic variant of the lactate dehydrogenase B subunit was found in the erythrocytes of the COP strain of the rat. The location of the band after the electrophoresis suggested a product of the structural gene for the B subunit. Two alleles that regulated the high amount (Ldh-2a) or the low amount (Ldh-2b) of the B subunit were found and segregated in Mendelian fashion. The activity was regulated by the closely linked (less than 1 cM) regulatory gene Ldr-1.

Alleles↗
PubMed1987

Interleukin-2 receptor levels are increased in blood of heart transplant patients during infections.

Increased levels of soluble interleukin-2 (IL-2) receptor were found in plasma of six patients after the heart transplantation. The levels peaked the first week after transplantation and then gradually decreased to normal levels. The moderate episodes of heart transplant rejection did not affect the IL-2 receptor levels in comparison to transplant recipients without the rejection episodes. However, the transplant patients with pneumonia had the IL-2 receptor levels ten times higher than healthy controls. Hence, the IL-2 receptor levels in plasma might be a valuable indicator of the dynamics of the acute infection in heart transplant recipients.

Fever↗
PubMed1984

Enhancement of adenosine 3',5'-monophosphate in human mononuclear and polymorphonuclear leukocytes by snake venoms.

Snake venoms contain compound(s) that enhanced cyclic AMP content in human mononuclear leukocytes maximally after 5 min of incubation at 37 degrees C. The effect was time- and dose-dependent. The half-maximal stimulation of cyclic AMP production by black cobra venom was found at 0.45 micrograms of venom/ml and the value of the Hill coefficient was 0.7. The black cobra venom enhanced the cyclic AMP content in the cells at 4, 22, and 37 degrees C. Similar increase in the cyclic AMP content by six snake venoms was found in human polymorphonuclear leukocytes. The most active venom was from puff adder (Bitis arietans). The data suggest that one of the effects of the snake venoms may be rapid enhancement of cyclic AMP level in the affected cells.

Alprostadil↗
PubMed1984

Linkage of diabetes insipidus and agouti genes in the rat.

Linkage of the hooded (h), agouti (A), and diabetes insipidus (di) genes was found in (ACI X DI)F1 X DI backcross rats. The genetic map distance A-di for females and for males was 19 +/- 5 and 28 +/- 5 cM, respectively. However, this difference was not significant. The combined data showed the map distance to be 25 +/- 4 cM. The three-point cross showed the following corrected distances and order of genes: h-42 +/- 4-A-25 +/- 4-di. However, the linkage of h and A, although significant (chi 2 = 9.03, P less than 0.001), is only tentative and must be confirmed by additional studies.

Animals↗