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F J Bollum

Publications and source records attributed to F J Bollum.

At least 19 recordsLinked to original sources
PubMed1995

Terminal deoxynucleotidil transferase is a nuclear PKC substrate.

Protein phosphorylation is the regulatory mechanism of many cellular events in response to changes in metabolic activity and environmental conditions. Seeing that PKC and TdT levels in cells are both regulated by PMA, we sought particularly intriguing to investigate TdT phosphorylation in vivo, utilizing KM-3 cells, a TdT-positive human pre-B cell line treated with PMA and in vitro, employing purified PKC and human recombinant TdT. Our data show that TdT is a substrate for PKC activity, suggesting that TdT phosphorylation could play a key role in the pathway affecting the control of gene transcription and protein synthesis during lymphoid cells differentiation.

Autoradiography↗
PubMed1992

Intracellular localization of terminal transferase during the cell cycle.

Changes in the localization of terminal transferase during the cell cycle in random cultures of human pre-T leukemia line RPMI-8402 were examined by light and electron microscopy on immunoperoxidase-stained preparations. Paraformaldehyde-fixed and saponin-permeabilized human cells were used with a monoclonal anti-human terminal deoxynucleotidyl transferase (TdT) primary reagent to demonstrate changes in enzyme distribution occurring between interphase and mitosis. Nuclear localization is found uniformly during interphase. At metaphase, however, the majority of TdT staining appears randomly distributed in the cytoplasm and traces of TdT staining remain associated with mitotic chromatin. At later phases, when the daughter cells are forming, the enzyme again appears to be restricted to the new nuclear structure.

Cell Cycle↗
PubMed1992

Immunocytochemical study of recombinant terminal deoxynucleotidyl transferase (TdT) synthesized by baculovirus-infected insect cells.

The ability to overproduce terminal transferase through recombinant DNA technology should provide alternate means for generating sufficient quantities for structural and mechanistic study of this creative DNA polymerase. In this work we have investigated, at electron microscope level, the morphological modification and ultrastructural localization of synthesized human terminal transferase occurring in Sf-9 cells during recombinant baculovirus infection time. The results obtained showed that TdT is localized and stored only at the cytoplasmic level; the nucleus did not show any specific site able to link the neosynthesized TdT. The amount of the enzyme, estimate by immunostaining analysis, increased with the viral infection time. Morphological changes occurring during viral infection consist mainly of variations of cellular surface, different size and shape of cytoplasmic organelles and modification of nuclear components.

Animals↗
PubMed1992

Ultrastructural localization of Terminal deoxynucleotidyl Transferase (TdT) in rat thymocytes.

TdT positive cells in rat thymus belong to distinct subsets as shown by light and electron microscopic immunocytochemistry. Using polyclonal antibodies to calf TdT and peroxidase labeled goat anti-rabbit IgG it has been possible to identify several subpopulations of TdT positive thymocytes. Large blasts corresponding to thymocytes at early maturational stages, are strongly positive for TdT which is diffusely distributed in both the nucleus and the cytoplasm. Smaller cells which correspond presumably to more advanced stages of maturation display nuclear TdT only, or are negative. Ultrastructural analyses of TdT indicate that the localization of the enzyme is related to the morphological features of the cells and TdT expression corresponds to maturational stages of T-cells.

Animals↗
PubMed1991

Primary structure and expression of bovine poly(A) polymerase.

Poly(A) polymerase has a critical role in the synthesis of messenger RNA in eukaryotic cells. The isolation and characterization of complementary DNAs encoding bovine poly(A) polymerase is described here. The predicted sequences of the mRNA and protein reveal features that provide insights into how the enzyme functions and how it might be regulated. Poly(A) polymerase expressed from a cloned cDNA is fully functional in in vitro assays, and mutational analyses have identified a putative regulatory domain that enhances, but is not essential for, activity.

Amino Acid Sequence↗
PubMed1991

Association between nuclear matrix and terminal transferase: an electron microscope immunocytochemical analysis.

Nuclear matrix extracted from KM-3, a human pre-B leukemia cell line, appears to have a site of linkage for terminal deoxynucleotidyl transferase (TdT). The immunocytochemical analysis of the distribution of TdT using a rabbit polyclonal antibody which recognizes human terminal transferase, shows that the nuclear framework of these cells contains sites of immunoreactivity that appear uniformly distributed on the matrix fibres, while the nucleolar region is unreactive. This evidence points out the possibility that TdT could reside in the proteinaceous scaffold of the nucleus defined as nuclear matrix, thus strengthening the evidence for the metabolic and regulatory roles ascribed to this nuclear framework.

Cell Line↗
PubMed1991

Quantitative assay of terminal deoxynucleotidyl transferase (TdT) activity using monoclonal antibodies.

Terminal deoxynucleotidyl transferase (TdT) is an important marker for the diagnosis and the therapy of leukemia and lymphoma patients. In this study, we developed the quantitative method for the assay of TdT antigen in leukemic cells using a combination of monoclonal and polyclonal antibodies prepared for this enzyme. High correlation was obtained between the values measured by biochemical assay and enzyme-linked immunosorbent assay (ELISA). This method (ELISA), using antibodies to TdT, permits the rapid and quantitative estimation of TdT antigen in leukemic cells.

Antibodies, Monoclonal↗
PubMed1990

Multiple roles of divalent cation in the terminal deoxynucleotidyltransferase reaction.

Terminal deoxynucleotidyltransferase activity is absolutely dependent on the presence of a divalent cation in the reaction mixture. This requirement can be satisfied by either Mg2+, Co2+, or Mn2+. When Mg2+ is used, the reaction rate is inhibited by metal ligands, and this inhibition can be reversed by Zn2+. Reaction rates in Mg2+ are also stimulated by the addition of micromolar amounts of Zn2+. To examine the role of Zn2+ in terminal transferase catalysis we analyzed for Zn2+ in homogeneous recombinant human terminal transferase preparations and found that Zn2+ is not an intrinsic part of enzyme molecule. Analysis of Zn2+ binding to terminal transferase under equilibrium conditions shows about 0.3 g of atom of Zn2+/mol of enzyme, suggesting that Zn2+ forms an easily dissociable complex with the enzyme molecule. Kinetic analyses showed that the stimulatory effect of Zn2+ is observed in several buffer systems. Zn2+ increases the affinity of the enzyme for the initiator about 2-fold and decreases affinity for dATP more than 10-fold, resulting in an increase in the apparent Vmax of the reaction. Using a 3'-ended 2',3'-dideoxyoligonucleotide as an inhibitor demonstrates that the inhibitor has no effect on the reaction rate in the absence of Zn2+ but is competitive with respect to the initiator in the presence of Zn2+. These results suggest that Zn2+ is a positive effector for terminal transferase, interacting with oligonucleotide and enzyme near the initiator binding site. Binding of Zn2+ to the enzyme appears to induce conformational changes that greatly increase the Vmax of the reaction with a concomitant decrease in the affinity of the enzyme for dNTP.

Adenosine Triphosphate↗
PubMed1990

Polyadenylic acid polymerase activity in chronic myelogenous leukemia.

Poly(A) polymerase activity was markedly elevated in CML in the blastic phase, moderately high in the accelerated phase and low in the chronic phase. The activity was significantly higher in the myeloid crisis than in the lymphoid crisis and elevated with increasing ratio of blasts in leukemia cases. In TPA or retinoic acid-treated leukemia cells poly(A) polymerase activity was decreased. These results suggest that poly(A) polymerase activity changes, depending on the maturation of leukemic cells and the assay of this enzyme activity may be useful for the early detection of the exacerbation of CML cases.

Blast Crisis↗
PubMed1989

Is terminal deoxynucleotidyl transferase an intracellular mutagen?

We have established stably transformed mammalian cell lines expressing recombinant human terminal deoxynucleotidyl transferase. A 58 kDa, enzymatically active protein is produced by these cell lines. Using the lacI gene of pJYMib shuttle vector as mutagenic target, we found no increase in mutation rates in cells expressing terminal deoxynucleotidyl transferase compared to controls. Our results suggest that the presence of terminal deoxynucleotidyl transferase alone in mammalian cells does not increase mutation rates.

Animals↗
PubMed1988

Expression and processing of recombinant human terminal transferase in the baculovirus system.

Overproduction of human terminal transferase protein has now been accomplished by cloning the coding sequence of human terminal transferase into a baculovirus, where the expression of terminal transferase is under the control of the polyhedrin protein promoter. Two constructs were made, one producing a protein containing the entire terminal transferase fused to 12 amino acids from the NH2 terminus of the polyhedrin protein, and the other producing 58-kDa human terminal transferase. The terminal transferase levels expressed in cells infected with either recombinant baculovirus are around 10,000 units/10(7) cells at 48 h postinfection, about 200-fold greater than levels expressed in thymus and cultured lymphoblastoid cells. The chimeric polyhedrin/human terminal transferase protein produced in the infected insect cells has a molecular weight of about 60,000 while the nonfused recombinant human terminal transferase is identical in molecular weight to that present in human lymphoblastoid cells. Both forms of recombinant terminal transferase show immunological and enzymatic activity. When infected cells are pulse-labeled with [35S] methionine at 42-45 h postinfection, about 10% of newly synthesized protein is terminal transferase. Both forms of terminal transferase are phosphorylated in recombinant virus-infected cells as demonstrated by pulse-labeling infected cells with 32P-inorganic phosphate and isolation of labeled terminal transferase peptides by immunoprecipitation.

Animals↗
PubMed1988

Chromosome sublocalization of a cDNA for human DNA polymerase-beta to 8p11----p12.

We have localized a cDNA fragment that codes for human DNA polymerase-beta. Using somatic cell and in situ hybridization techniques, this cDNA was cloned by screening a human KM-3 cell cDNA library in lambda gt 11 for expression of fused beta-galactosidase-human DNA polymerase-beta proteins. We have mapped this human polymerase-beta gene to the short arm of chromosome 8 in the subregion 8p11----p12.

Animals↗
PubMed1988

Phenotypic and molecular heterogeneity in Philadelphia chromosome-positive acute leukemia.

Philadelphia chromosome-positive (Ph1) acute leukemia is a heterogeneous subset of acute leukemia with a poor prognosis. We studied five patients to determine the potential for phenotypic and molecular heterogeneity. Cellular characterization studies included light myeloperoxidase (L-MPO), terminal deoxynucleotidyl transferase (TdT), ultrastructural MPO (U-MPO), and immunophenotyping by flow cytometry using T11, T3, T4, T8, Leu 1, B1, Leu 12, HLA-DR (la), CALLA (J5), OKM1, My4, My7, My8, My9, and My10. DNA was analyzed for rearrangements of the breakpoint cluster region (bcr), immunoglobulin heavy chain, joining region (JH), immunoglobulin kappa light chain constant region (C kappa), and T cell receptor (TcR beta). RNA dot blots were hybridized by using molecular probes for MPO and TdT. We found that four of five cases were acute mixed-lineage leukemia (AMLL). One patient had acute unclassifiable leukemia. Of the four patients classified as having AMLL, three showed myeloid and lymphoid features, with one patient showing myeloid, T cell, and B cell features. The last case showed T cell and B cell features only. In one patient MPO/RNA was positive in spite of insufficient L-MPO or U-MPO to diagnose acute myelogenous leukemia (AML), thereby suggesting significant MPO gene expression before the production of sufficient MPO protein to meet the French-American-British criteria for AML. Three of the five patients showed rearrangement of bcr (cases 1, 2, and 5). Studies of these five patients support the concepts of molecular and phenotypic heterogeneity in Ph1 acute leukemia, demonstrate a high incidence of AMLL in this subset of acute leukemia, and support the use of lineage-associated molecular probes to define lineage at an earlier stage than previously possible.

Acute Disease↗
PubMed1987

HL-T, a new cell line derived from HL-60 promyelocytic leukemia cell cultures expressing terminal transferase and secreting suppressor activity.

A cell line with immature blast cell morphology was isolated from HL-60 promyelocytic leukemia cell cultures and designated HL-T. This new cell type is biphenotypic, expressing terminal transferase (TdT) together with myelomonocytoid immunologic features. TdT enzymatic activity, undetectable in HL-60, was determined to be 140 to 180 units/10(8) HL-T cells by the dGTP-assay, approximately 20% of the activity found in lymphoblastoid cell lines. HL-T predominantly synthesize the known 58-kDa TdT-protein plus a minor 54/56-kDa doublet. The 58-kDa steady state form is nonglycosylated and is phosphorylated. Precursor antigens S3.13 and MY-10, absent on HL-60, are expressed by HL-T; however, the cells are negative for HLA-Dr. Southern blot analysis by hybridization with immunoglobulin heavy chain (JH) and T cell-receptor chain gene (T beta) probes shows JH to be in the germ-line configuration in both cell lines and the T beta gene to be in germ-line in HL-60 but to be rearranged in HL-T. Truncation of the gene encoding the granulocyte-macrophage-colony-stimulating factor (GM-CSF), as found in HL-60, is not observed in HL-T. HL-T are resistant to differentiation-induction by retinoic acid and 1,25-dihydroxyvitamin D3. Cytogenetically HL-T share with HL-60 a deletion of the short arm of chromosome 9 at breakpoint p13, an aberration frequently found in patients with T cell leukemia. In addition, HL-T display t(8;9)(p11;p24) and trisomy 20. Tetraploidy is observed in 80% of HL-T metaphases with aberrations identical to those in the diploid karyotype. Like HL-60, the new line shows some surface-antigenic-T cell characteristics. Despite an antigenic pattern most consistent with that of helper-inducer T cells (T4+, D44+/-, 4B4+, 2H4-, TQ1+/-), HL-T cells and their conditioned culture medium suppress antigen, mitogen, and mixed-leukocyte-culture-mediated lymphocyte proliferation.

Cell Line↗
PubMed1987

Immunoenzymatic method for detection of terminal deoxynucleotidyl transferase by light and electron microscopy.

Methods for using rabbit polyclonal and mouse monoclonal antibodies to detect terminal deoxynucleotidyl transferase (TdT) in human leukemia lines were developed. Use of 1% paraformaldehyde in 0.1 M Na cacodylate buffer, pH 7.6, as a fixative provides a procedure that can be used for immunofluorescence, immunoalkaline phosphatase (APAAP), or horseradish peroxidase conjugate detection procedures in these cell lines. The peroxidase procedure can also be used for electron microscopy, clearly demonstrating nuclear localization of TdT in interphase nuclei of TdT-positive cells.

Alkaline Phosphatase↗
PubMed1986

Defective lymphopoiesis in bone marrow of motheaten (me/me) and viable motheaten (mev/mev) mutant mice. I. Analysis of development of prothymocytes, early B lineage cells, and terminal deoxynucleotidyl transferase-positive cells.

This study identifies defects in the early stages of lymphopoiesis that may contribute to the abnormalities in the development and/or function of peripheral T and B lymphocytes in mice homozygous for the motheaten (me/me) and viable motheaten (mev/mev) mutations. The results indicate that in me/me and mev/mev mice prothymocytes in bone marrow are present in essentially normal numbers, as determined by intrathymic injection, but apparently lack the ability to home effectively to the thymus, as determined by intravenous transfer; early B lineage cells in bone marrow, identified by the B220 antigen, are markedly depleted, including immature B cells (sIg+), pre-B cells (cIg+, sIg-), and pro-B cells (B220+, cIg-, sIg-); TdT+ bone marrow cells, especially a subset that expresses the B220 B lineage antigen, are markedly depleted by two weeks of age; normal numbers of TdT+ thymocytes are present during the first 3 wk of postnatal life, but rapidly decrease thereafter. The results further indicate that neither the defective thymus homing capacity of prothymocytes nor the deficiency of TdT+ bone marrow cells is due to autoantibodies. The possible relationship of the defective development of lymphoid precursor cells to the premature onset of thymic involution and to the abnormalities of peripheral T and B lymphocytes in me/me and mev/mev mice is discussed; as are the results of in vitro studies (presented in a companion paper), which suggest that a primary defect in the stromal microenvironment of the bone marrow is responsible for the abnormal development of the lymphoid precursor cells.

Animals↗
PubMed1986

Immunological analysis of the polypeptide structure of calf thymus DNA polymerase-primase complex.

Five major polypeptides are found in immunoaffinity-purified calf thymus DNA polymerase-DNA primase complex: 185, 160, 68, 55, and 48 kDa. Individual polypeptides purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were used to produce antibodies in rabbits to aid in identifying the relationships between these polypeptides by immunoblotting and enzyme neutralization procedures. Immunoblot analyses showed that the 160-kDa peptide is derived from the 185-kDa peptide and the 48-kDa peptide is derived from the 68-kDa peptide while antibodies to the 55-kDa peptide do not cross-react with other peptides found in the complex. Direct enzyme neutralization studies demonstrated that antibodies to 185- and 160-kDa peptides inhibit DNA polymerase activity in the complex, confirming earlier suggestions that these peptides are the catalytic peptides for DNA polymerase. DNA primase activity in the complex is inhibited by antibodies to 68-, 55-, and 48-kDa peptides and to a lesser extent by antibodies to the 160-kDa peptide. Free DNA primase isolated from the complex was estimated to have a native molecular weight of about 110,000. The 55- and 48-kDa peptides are found to be associated with the free primase activity. Rabbit antibodies to both 55- and 48-kDa peptides are inhibitory to this primase activity. From these results we suggest that the native calf thymus DNA polymerase-DNA primase complex contains only three unique peptides with the 185-kDa peptide as the catalytic peptide of DNA polymerase and the 55- and 68-kDa peptides constituting the primase peptides. A model illustrating the roles of these peptides in initiation and replication of DNA is presented.

Animals↗