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Biomedical subjects

C Peschle

Publications and source records attributed to C Peschle.

At least 109 records · Page 6Linked to original sources
PubMed1994

Coordinate expression and proliferative role of HOXB genes in activated adult T lymphocytes.

We investigated the expression of HOXB cluster genes in purified phytohemagglutinin (PHA)-activated T lymphocytes from normal adult peripheral blood by reverse transcription PCR and RNase protection. These genes are not expressed in quiescent T cells, except for barely detectable B1 RNA. After the PHA stimulus, HOXB gene activation initiates coordinately as a rapid induction wave in the 3'-->5' cluster direction (i.e., from HOXB1 through B9 genes). Thus, (i) expression of the foremost 3'-located B1 and B2 genes peaks 10 min after PHA addition and then rapidly declines, (ii) activation of B3, B4, and B5 begins 10 min after PHA addition and peaks at later times (i.e., at 120 min for B5), (iii) B6, B7, and B9 are expressed at a low level starting at later times (45 to 60 min), and (iv) B8 remains silent. Treatment of PHA-activated T lymphocytes with antisense oligonucleotides to B2 or B4 mRNA causes a drastic inhibition of T-cell proliferation and a decreased expression of T-cell activation markers (i.e., interleukin 2 and transferrin receptors). Similarly, treatment of CEM-CCRF, Peer, and SEZ627 T acute lymphocytic leukemia cell lines with anti-B4 oligomer markedly inhibits cell proliferation. Finally, T cells stimulated by a low dosage of PHA in the presence of 1 microM retinoic acid show a marked increase of both HOXB expression, particularly B2, and cell proliferation. These studies provide novel evidence on the role of HOX genes in adult cell proliferation. (i) Coordinate, early activation of HOXB genes from the 3'-->5' cluster side apparently underlies T-cell activation. (ii) The expression pattern in adult PHA-activated T cells is strikingly similar to that observed in retinoic acid-induced teratocarcinoma cells (A. Simeone, D. Acampora, L. Arcioni, P. W. Andres, E. Boncinelli, and F. Mavilio, Nature (London) 346:763-766, 1990), thus suggesting that molecular mechanisms underlying HOX gene expression in the earliest stages of development may also operate in activated adult T lymphocytes.

Adult↗
PubMed1994

High dose-intense chemotherapy alone or in combination with interleukin-2 for small cell lung cancer: a pilot study.

Given the antitumor activity of interleukin-2 (IL-2) against some drug-resistant cancer cells, 17 previously untreated patients with small cell lung cancer entered a pilot study to evaluate the feasibility, efficacy, and immunological effects of combining 12-week high dose-intense chemotherapy based on a modified Evans regimen (CAV/PE) with different IL-2 schedules (6-12 MU/m2 week as a 48-72-h infusion using the same cumulative dose, 72 MU/m2). Despite significant myelotoxicity, up to 70% of the intended dose intensity was delivered, showing no differences with regard to the IL-2 schedule used. Immunotherapy-induced toxicity was usually mild and manageable. No limiting effects were observed in patients receiving immunotherapy except for a very poor compliance to the 12-week IL-2 regimen. The low-dose 72-h infusion was the optimal IL-2 schedule. As given in this study, neither of the alternating CAV/PE regimens abrogated the effects of IL-2 on T-cell and NK-cell subsets, showing typical kinetics with rebound in lymphocytes following each discontinuation of the IL-2. While immunological changes cannot predict the antitumor effect of IL-2, they are consistent with those described for IL-2 alone, suggesting its compatibility with high dose-intense chemotherapy. Although no definite advantages have been demonstrated in this small pilot study with significant unbalanced prognostic factors (12% 2-year survival), both the preserved immunostimulatory effects and the lack of limiting overlapping toxicity make this combined approach promising and worthy of further clinical investigation.

Adult↗
PubMed1994

c-fes expression in ontogenetic development and hematopoietic differentiation.

The c-fes protein (NCP92) is a tyrosine-specific protein kinase, capable of both autophosphorylation and phosphorylation of other substrates. We have analysed c-fes RNA expression in human/murine ontogenetic development and in homogeneous populations of embryonic and adult human hematopoietic cells. c-fes expression has been observed in rapidly proliferating embryonic-fetal tissues originating from different germinal layers, but not in adult non-hematopoietic tissues. In particular, a spatially and temporally regulated transcription was observed in the central nervous system and in developing cartilage. Expression in hematopoietic cells was evaluated in progenitors purified from embryonic-fetal liver and adult peripheral blood differentiating gradually and specifically along the erythroid or granulomonocytic lineage. In both embryonic and adult hematopoietic cells c-fes was abundantly expressed in undifferentiated progenitors of both lineages, as well as in differentiated granulomonocytic precursors, but not in erythroblasts. This expression pattern correlates with that of GM-CSF and in part IL-3 receptors (Testa et al., 1993 and our unpublished results). Altogether, these results suggest a possible role for c-fes in signal transduction, in both embryonic non-hematopoietic tissues and embryonic/adult hematopoietic cells, following interaction of growth factors with their tyrosine-kinase negative receptors (i.e., GM-CSF and IL-3 receptors in adult hematopoietic cells and other hypothetical growth factor(s) receptors during embryonic development.

Adult↗
PubMed1993

The acute promyelocytic leukemia-specific PML-RAR alpha fusion protein inhibits differentiation and promotes survival of myeloid precursor cells.

Acute promyelocytic leukemia is a clonal expansion of hematopoietic precursors blocked at the promyelocytic stage. The differentiation block can be reversed by retinoic acid, which induces blast maturation both in vitro and in vivo. Acute promyelocytic leukemia is characterized by a 15;17 chromosome translocation with breakpoints within the retinoic acid alpha receptor (RAR alpha) gene on 17 and the PML gene, which encodes a putative transcription factor, on 15. A PML-RAR alpha fusion protein is formed as a consequence of the translocation. We expressed the PML-RAR alpha protein in U937 myeloid precursor cells and showed that they lost the capacity to differentiate under the action of different stimuli (vitamin D3 and transforming growth factor beta 1), acquired enhanced sensitivity to retinoic acid, and exhibited a higher growth rate consequent to diminished apoptotic cell death. These results provide evidence of biological activity of PML-RAR alpha and recapitulate critical features of the promyelocytic leukemia phenotype.

Animals↗
PubMed1993

Transforming growth factor-beta potentiates vitamin D3-induced terminal monocytic differentiation of human leukemic cell lines.

We have investigated the effects of 1,25-dihydroxyvitamin D3 (D3) and/or transforming growth factor (TGF)-beta on one monocytic (U-937) and two human promyelocytic (HL-60 and AML-193) leukemic cell lines. D3 addition induces a partial monocytic maturation of the cell lines, whereas TGF-beta treatment is largely ineffective. Combined treatment with TGF-beta and D3 causes terminal monocytic maturation, as evaluated both by assessment of a large spectrum of membrane Ag and by functional assays. Furthermore, sequential addition of the two inducers showed that pretreatment with TGF-beta 1 followed by incubation with D3, but not vice versa, induces monocytic maturation as effectively as simultaneous treatment with both agents. In liquid culture the proliferative activity of these cell lines is slightly decreased by D3 and virtually unaffected by TGF-beta, whereas combined treatment with D3 and TGF-beta induces a markedly potentiated inhibitory effect. Furthermore, TGF-beta/D3 treatment (but not D3 alone) elicits the expression of membrane CD14, FcRI, FcRII, CD11a, CD11b, CD11c, ICAM-1, and PECAM-1 Ag at a level comparable to that observed on normal human monocytes. It is noteworthy that several of these Ag play an important role in monocyte physiology (e.g., CD14 Ag mediates the binding of bacterial LPS to monocytes). Treatment with both TGF-beta and D3 (but not D3 alone) induces superoxide anions and H2O2 production similar to that of circulating monocytes. In semisolid culture, D3 and TGF-beta alone cause, respectively, a marked and slight loss of cloning efficiency of the cell lines, whereas their combined addition synergistically results in a complete loss of the cloning capacity. These findings suggest a physiologic role for TGF-beta in monocyte maturation. Furthermore, they may pave the way to the design of clinical protocols combining D3 and TGF-beta in the differentiation therapy of acute promyelocytic/myelomonocytic leukemia.

Adjuvants, Immunologic↗
PubMed1993

Cascade transactivation of growth factor receptors in early human hematopoiesis.

Highly purified progenitors (including erythroid [BFU-E], granulo-monocytic [CFU-GM], multipotent [CFU-GEMM] progenitors, as well as multipotent progenitors with self-renewal capacity [CFU-B]) express high-affinity growth factor receptors (GFRs), with prevalent interleukin-3 receptors (IL-3Rs) (2,700/cell), a > or = 10-fold lower number of IL-6Rs (145/cell) and granulocyte-macrophage colony-stimulating factor receptors (GM-CSFRs) (300/cell), and a barely detectable level of erythropoietin (Ep) receptors (75/cell). Hematopoietic growth factor (HGF) dosages inducing peak clonogenetic effects are associated with partial/subtotal occupancy of the homologous HGF receptor (HGFR). Cross-reactivity between GFRs and heterologous GFs (including IL-6, IL-3, GM-CSF, Ep, and the kit ligand [KL]) was explored by competition experiments on purified progenitors with radiolabeled and excess cold HGFs at +4 degrees C. No cross-reaction was observed between IL-6R, IL-3R, EpR, and the heterologous GFs, whereas the GM-CSFR showed cross-reactivity with IL-3 and, to a lesser extent, KL. Modulation of GFRs was examined after 18 or 40 hours of incubation with GF(s) at 37 degrees C, followed by ligand-binding assay at 20 degrees C. IL-6, IL-3, GM-CSF, and Ep induce a marked down-modulation of their own receptors. Interestingly, each GF induces the transactivation of the R(s) for the "distal" GF(s): (1) IL-6 induces transactivation of IL-3R, but not of GM-CSFR/EpR; (2) IL-3 causes a rapid upmodulation of GM-CSFR/EpR ("pure" progenitors treated with IL-3 show upmodulation of GM-CSFR alpha-chain mRNA by reverse transcriptase-polymerase chain reaction); whereas (3) GM-CSF induces the transactivation of the EpR. This chain upmodulation of HGFRs may underlie the synergistic interactions between the HGFs in clonogenetic culture. It is emphasized that KL does not induce upmodulation of the other GFRs. Finally, Ep, GM-CSF, and IL-3 do not modulate the expression of the "proximal" HGFRs (ie, GM-CSFR/IL-3R/IL-6R, IL-3R/IL-6R, and IL-6R, respectively). These results allow insight into the cellular basis of hematopoiesis, ie, the complex and coordinate interactions between HGFs and their receptors. They are compatible with a model of cascade transactivation via upmodulation of GFRs in the initial key steps of hematopoietic differentiation, whereby the action of each GF enhances the effect of the distal GF(s) by a multistep chain-potentiation mechanism.

Adult↗
PubMed1993

Combined interleukin 1 beta/interleukin 2 treatment in mice: synergistic myelostimulatory activity and protection against cyclophosphamide-induced myelosuppression.

We have studied the effects of single and combined treatment with interleukin 1 beta (IL-1 beta) and interleukin 2 (IL-2) on spleen and bone marrow hematopoiesis in normal mice. Injection of IL-1 beta alone was followed by a significant increase in the number of granulocytes in spleen and progenitors (burst-forming units-erythroid and colony-forming units-granulomonocytic) in both spleen and bone marrow, s compared to control mice. In contrast, IL-2 alone induced only a slight increase in the number of marrow colony-forming units-granulomonocytic and had no significant effect on spleen progenitors. Repeated injections of both IL-1 beta and IL-2 resulted in a synergistic increase in spleen weight and splenocyte number, as compared to mice treated with the single cytokine regimen; in particular, the combined treatment induced a marked rise in the number of neutrophilic granulocytes and erythroblasts, whereas splenic lymphocytes were not affected. This regimen also caused a synergistic increase in the number of spleen and marrow progenitor cells: a time-course analysis showed an elevation in numbers of both burst-forming units-erythroid and colony-forming units-granulomonocytic, first in marrow (day 10) and subsequently in spleen (day 18). Combined IL-1 beta/IL-2 treatment dampened the decrease and accelerated the recovery of myeloid cells after cyclophosphamide injection, whereas the single cytokine regimen was not effective. Similarly, the rebound of WBC (especially neutrophilic granulocytes) after cyclophosphamide treatment was markedly enhanced by the combined treatment, whereas the single cytokine regimen was ineffective. These results, indicating a myelostimulatory effect by the combined cytokine regimen, together with our previous observations showing a synergistic antitumor activity by IL-1/IL-2 treatment in experimental mouse tumors (V. Ciolli et al., J. Exp. Med., 173: 313-322, 1991), may provide the basis for the development of new combination therapies with cytokines and antiblastic agents in the treatment of cancer patients.

Animals↗
PubMed1993

c-kit ligand reactivates fetal hemoglobin synthesis in serum-free culture of stringently purified normal adult burst-forming unit-erythroid.

We have analyzed the reactivation of fetal hemoglobin (HbF) synthesis under rigorous in vitro conditions, ie, in mature erythroblasts generated by erythroid burst-forming units (BFU-E) stringently purified from normal adult peripheral blood and grown in fetal calf serum(FCS)-free semisolid or liquid phase culture. In clonogenetic dishes, graded amounts of c-kit ligand (KL) were added together with saturating levels of erythropoietin (Ep) and variable amounts of interleukin-3 and granulocyte-macrophage colony stimulating factor (IL-3/GM-CSF), ie, high or low level, or no IL-3/GM-CSF addition. In all conditions, KL induced a sharp, dose-dependent increase in the percentage of F cells and HbF content from nearly normal levels (< 10% and < 2.5%, respectively, at 0.1 and 1 ng/mL) up to 40% to 50% and 10% to 15% at 100 to 200 ng/mL. This increase was not associated with significant differences of burst number or stage of maturation at the time of analysis (as evaluated on the basis of percent mature erythroblasts and Hb content per cell). However, the KL-induced reactivation of HbF synthesis was strictly and directly correlated with a sharp increase of colony size, ie, cell number per burst. Addition of large amounts of IL-3 and GM-CSF (10 to 100 U and 1 to 10 ng/mL, respectively) significantly potentiated the KL-induced reactivation of HbF, as compared with low levels (0.1 U and 0.01 to 0.1 ng) or no addition of these growth factors: this increase was highly significant at low KL doses (ie, 1 to 10 ng/mL). Single-burst analysis showed that the KL-induced HbF reactivation occurs homogeneously in the erythroid colonies within each of these culture conditions. We have analyzed the effect of KL in liquid phase BFU-E culture treated with the IL-3/GM-CSF/Ep combination at sequential times until terminal erythroid maturation: KL causes a sharp increase in the percentage of F cells and HbF content in all stages of maturation, whereas the IL-3/GM-CSF/Ep combination alone has a markedly lower effect. These results suggest that KL plays a key role in the reactivation of HbF synthesis in adult life, whereas IL-3/GM-CSF potentiate this effect at low KL levels. The KL-induced HbF reactivation is seemingly related to an enhanced proliferation of erythroid progenitors in the erythropoietic differentiation pathway.

Adult↗
PubMed1993

Stringently purified human hematopoietic progenitors/stem cells: analysis of cellular/molecular mechanisms underlying early hematopoiesis.

Analysis of the cellular/molecular basis of the early steps of hematopoietic proliferation and differentiation is hindered by the rarity of hematopoietic progenitors and stem cells (HP/HSC). The intensive efforts devoted to the development of purification methods for early HP and HSC, although initially largely unsuccessful, have recently provided a high level of HP/HSC yield and/or recovery. The methodology developed by our group, recently improved, provides not only virtually complete purification, but also abundant recovery of early HP/HSC such as colony forming units granulocyte/erythroid/macrophage/megakaryocyte (CFU-GEMM), burst forming units erythroid (BFU-E), CFU granulocyte/macrophage (CFU-GM)/CFU blast cells (CFU-B), and long-term culture initiating cells (LTC-IC) from adult peripheral and cord blood (CB). We have also developed a serum-free liquid suspension culture for unilineage erythroid (E), granulocytic (G) or monocytic (M) differentiation of stringently purified HP/HSC. These culture systems allow sequential collection and cellular/molecular analysis of discrete populations of hematopoietic cells at a homogenous stage of differentiation specifically along a unilineage pathway. These experimental tools have been utilized to investigate cellular/molecular mechanisms underlying early hematopoiesis. The transcription factor (TF) GATA-1 is considered to be the "master" gene of erythropoiesis. In highly purified HP/HSC undergoing E or GM differentiation, GATA-1 expression is characterized initially by proliferation-dependent activation and at later stages by sustained expression in the E pathway and suppression in the GM pathway. Hypothetically, similar on/off switches of lineage-restricted TF may underlie the binary fate decisions of early HP differentiation. The expression and modulation of hematopoietic growth factor receptors (HGFR) in early hematopoiesis have been extensively analyzed. The results suggest a model of transactivation cascade for HGFR such as interleukin 6 receptor (IL-6R), IL-3R, GM colony stimulating factor receptor (GM-CSFR), and erythropoietin receptor (EpR), whereby each HGF upmodulates the R(s) for distal-acting HGF(s). Finally, we have investigated the effect of HGF on reactivation of hemoglobin F (HbF) in clonogenic or liquid suspension serum-free culture of purified adult HP. The results suggest that c-kit ligand (KL) plays a key role in the reactivation of HbF synthesis in adult life, and IL-3/GM-CSF potentiate this effect at low KL level. The KL-induced HbF reactivation is seemingly related to an enhanced proliferation of early E progenitors in their differentiation pathway.

Animals↗
PubMed1993

Mannoprotein-induced anti-U937 cell cytotoxicity in peripheral blood mononuclear cells from uninfected or HIV-infected subjects: role of interferon-gamma and tumor necrosis factor-alpha.

A mannoprotein fraction (MP-F2: mannan, > 90%; protein, 4.5%) from the human commensal microorganism Candida albicans was as efficient as interleukin-2 (IL-2) in generating cytotoxicity against the uninfected or human immunodeficiency virus type-1 (HIV-1) persistently infected monocytoid U937 cell line in cultured peripheral blood mononuclear cells (PBMC) from healthy human subjects. MP-F2-activated killing of U937 cells (U937-MAK) decreased progressively with advancing stages of HIV-1 infection to virtually no killing effect in PBMC from advanced AIDS subjects (AIDS PBMC). This decrease paralleled a lowered susceptibility of U937 cells to natural killer cell activity. In contrast, IL-2-activated killing of U937 cells (U937-LAK) was not affected by the progression of HIV infection and persisted at high levels in AIDS PBMC. To shed light on the mechanisms of U937-MAK and its decrease during HIV infection, IL-1 beta, IL-6, TNF-alpha, GM-CSF, and IFN-gamma production was analyzed. Decreases in TNF-alpha, GM-CSF, and IFN-gamma, but not IL-1 beta or IL-6, levels were observed in MP-F2-stimulated PBMC from HIV-infected subjects, compared to healthy controls. Interestingly, these cytokine levels fell before the onset of AIDS. The greatest relative drop was that of IFN-gamma, from 4600 (+/- 600) to 290 (+/- 160) and 217 (+/- 110) mean pg/ml (+/- SE) in PBMC from healthy donors (11 subjects), CDC stages II + III (14 subjects), and CDC stage IV (10 subjects), respectively. The following observations suggest that decreased IFN-gamma production plays a role in the abrogation of U937-MAK activity: (i) addition of neutralizing anti-IFN-gamma antibodies abolished both IFN-gamma and U937-MAK activity in PBMC from healthy subjects; (ii) substantial levels of IFN-gamma were detected in supernatants of PBMC cultures stimulated by IL-2, in line with preserved U937-LAK activity. Interestingly, anti-IFN-gamma antibodies also abolished TNF-alpha production, and the anti-TNF-alpha antiserum effect was comparable to that of anti-IFN-gamma in U937-MAK inhibition. In contrast, anti-TNF-alpha antibodies abrogated TNF-alpha activity, but only partially reduced IFN-gamma production. Thus, in human PBMC, U937-MAK activity progressively decreases with advancing stages of HIV infection, whereas U937-LAK activity is sustained. Furthermore, the present results indicate a pivotal role for IFN-gamma in U937 MAK activity, possibly through activation of TNF-alpha production.

Adult↗
PubMed1993

Susceptibility of human liver cell cultures to hepatitis C virus infection.

To develop a cell culture system susceptible to infection by hepatitis C virus (HCV), human fetal hepatocytes, grown in serum-free medium, were inoculated with serum samples from two HCV-infected patients. Viral RNA sequences were detected by polymerase chain reaction, using primers specific for the 5' noncoding region of HCV, in extracts prepared from the hepatocyte cultures as early as 5 days after inoculation. Virus was also released from the infected cells into the medium. The HCV strains could be serially passaged three times into fresh liver cell cultures using intracellular virus as inoculum. Evidence that HCV replication really took place in primary human fetal hepatocytes was also obtained by detection of minus-strand viral RNA (replication intermediate) in cell extracts and of viral antigens in the infected cells.

Base Sequence↗
PubMed1993

The transferrin receptor.

Transferrin receptor (TfR) is a membrane receptor involved in the control of iron supply to the cell through the binding of transferrin, the major iron-carrier protein. This receptor plays a key role in the control of cell proliferation because iron is essential for sustaining ribonucleotide reductase activity, and is the only enzyme that catalyzes the conversion of ribonucleotides to deoxyribonucleotides. Furthermore, TfR is overexpressed in several tumors. The synthesis of the receptor is controlled through an iron-dependent negative feedback in cells where the receptor is involved in the control of cell proliferation, but through a positive feedback in cell types involved in iron storage (monocytes-macrophages). Recent studies have shed light on the molecular basis by which iron regulates TfR expression. Thus, the 3' untranslated region of TfR mRNA contains a cis-acting RNA element, termed the iron-regulatory element (IRE), that interacts with an IRE-binding protein (IRE-BP). The high-affinity interaction between IRE-BP and IRE in the TfR mRNA leads to repression of mRNA degradation and thus to higher synthesis of TfR. Hence, the study of IRE-BP activity will elucidate the mechanisms that modulate TfR expression in normal and malignant cells.

Amino Acid Sequence↗
PubMed1992

Production of hemolymphopoietic cytokines (IL-6, IL-8, colony-stimulating factors) by normal human astrocytes in response to IL-1 beta and tumor necrosis factor-alpha.

Astrocyte-enriched populations were established from human embryonic brain analyzed for their ability to synthesize cytokines potentially relevant for mechanisms of inflammation and immunity in the brain. Unstimulated astrocytes did not secrete significant IL-6, IL-8, macrophage CSF (M-CSF), granulocyte-macrophage CSF (GM-CSF), or granulocyte-CSF (G-CSF), as determined by specific ELISA and/or bioassay. With the exception of M-CSF mRNA, transcripts for the above factors were not detected in unstimulated astrocytes. On exposure of human astrocytes to IL-1 beta, high levels of IL-6, IL-8, M-CSF, G-CSF, and GM-CSF mRNAs were detected; moreover, active secretion of all the above cytokines was demonstrated. TNF-alpha was also able to stimulate IL-6, IL-8, M-CSF, GM-CSF, and G-CSF synthesis and secretion, but was generally less potent than IL-1 beta. No IL-3 mRNA or protein was detected in unstimulated or cytokine-treated astrocytes. IL-1 alpha and IL-1 beta mRNAs and proteins were not detected in unstimulated astrocytes, but were present in very small amounts after stimulation with TNF-alpha/IL-1 beta. No IL-6, M-CSF, GM-CSF, G-CSF, or IL-8 were induced by IL-1 beta or TNF-alpha in early primary cultures, which mainly contain undifferentiated neuronal/glial progenitor cells. These studies demonstrate for the first time the production of multiple cytokines by normal human astrocytes stimulated in culture by IL-1 beta and TNF-alpha. The capacity of human astrocytes to synthesize and release cytokines active on hemolymphopoietic cells supports the concept that these cells play an important role in the regulation of inflammatory and immune responses in a variety of brain pathologies.

Astrocytes↗
PubMed1992

Developmental switching of messenger RNA expression from the human alpha-globin cluster: fetal/adult pattern of theta-globin gene expression.

The alpha-globin gene cluster contains four functional globin genes, zeta, alpha 2, alpha 1, and theta. The developmental regulation of the embryonic zeta and fetal/adult alpha 2- and alpha 1-globin genes is well characterized at the level of protein synthesis. The developmental pattern of the theta-globin gene is not well characterized due to the inability to detect its encoded protein. Direct analysis of the globin switching at the steady-state messenger RNA (mRNA) level has been hampered by the difficulty in obtaining quantities of embryonic and early fetal mRNA sufficient for analysis. We analyzed the relative levels of the steady-state zeta-, alpha-, and theta-globin mRNAs in yolk sac in 5-, 6-, 7-, and 8-week postconception embryonic liver, and in cord and adult blood reticulocytes. We show that the switch in the alpha-globin gene cluster from the embryonic to fetal/adult pattern of expression begins at 5 to 6 weeks of gestation. Both the theta- and alpha-globin genes show similar patterns of developmental control that are reciprocal to zeta. alpha-globin RNA is barely detectable or undetectable at 5 weeks, and increases in the 6- to 8-week period, while theta-globin mRNA shows a parallel increase at 5 to 8 weeks postconception and is expressed in cord blood and adult reticulocytes. These data show that the theta-globin gene represents a fetal/adult gene, albeit expressed at a low level.

Adult↗
PubMed1992

A human HOX4B regulatory element provides head-specific expression in Drosophila embryos.

Like other homeobox genes of the Antennapedia and bithorax complexes (collectively called the HOM complex), the Drosophila Deformed (Dfd) gene has structural homologues in the Hox/HOX complexes of mouse and humans, one of which is human HOX4B (refs 3, 4). Previous experiments indicated that HOX4B protein can specifically activate the expression of the endogenous Dfd transcription unit in Drosophila embryos and larvae. We therefore asked whether HOX4B cis-regulatory elements could mimic the function of a Dfd autoregulatory element in Drosophila embryos. Here we show that a HOX4B upstream element can surprisingly provide expression in a posterior head segment of Drosophila. One possible mechanism for the axial position-specificity of the human element may involve the conservation of a Dfd-specific autoregulatory circuit in both arthropod and chordate lineages. This possibility is supported by the finding that a Drosophila Dfd autoregulatory element supplies spatially localized expression in the hindbrain of mouse embryos.

Animals↗
PubMed1992

Expression of selected human HOX-2 genes in B/T acute lymphoid leukemia and interleukin-2/interleukin-1 beta-stimulated natural killer lymphocytes.

Although the key role of human homeobox (HOX) genes in development is well established, their function in adult cells is still under scrutiny. We have analyzed, in normal adult blood cell subpopulations, acute lymphoid leukemia (ALL) cells lines, and primary blasts, the RNA expression of all HOX-2 cluster genes (5'-2.5, 2.4, 2.3, 2.2, 2.1, 2.6, 2.7, 2.8, 2.9, 3') and nine genes in the HOX-1, -3, and -4 cluster by Northern blotting, RNAse protection, and/or reverse transcriptase polymerase chain reaction (RT-PCR). The analyzed HOX-1, -3, and -4 genes were never expressed in all tested cell populations. Natural killer (NK) cells activated in interleukin-2 (IL-2)/IL-1 beta-treated cultures exhibit a gradually increasing, abundant expression of three HOX-2 genes (2.2, 2.6, 2.8), while three other genes (2.3, 2.1, 2.7) are expressed at a lower level at late culture times. However, no HOX-2 gene is expressed in quiescent lymphocytes (NK, B and T [T-cell receptor (TCR) alpha/beta, gamma/delta lymphocytes, thymocytes] cells), granulocytes, and monocytes. In B- and T-ALL cell lines, HOX-2 genes are expressed according to different patterns: (1) widespread transcription (seven of nine genes, including 2.3 and 2.6) in the Peer line bearing the TCR gamma/delta; (2) expression of 2.5, 2.2, and 2.6 in the SEZ 627 line, which derives from an HTLV-1+ T-helper leukemia; (3) transcription of 2.3 and 2.6 in both the T-ALL CEM line and four B-ALL lines (interestingly, CALLA- B-ALL lines are constantly 2.3/2.6 RNA+); (4) no HOX-2 gene expression was detected in one T- and two B-ALL lines. Primary blasts from five T- and five pre-B-ALL showed selective expression of one or more HOX-2 genes, namely 2.5, 2.2, 2.6, and 2.7. Our data are compatible with the hypothesis that selected HOX-2 genes play a role in the IL-2/IL-1 beta-induced activation and/or proliferation of normal NK lymphocytes and possibly in the oncogenetic process of some T- and B-ALL.

Base Sequence↗
PubMed1992

Post-transcriptional regulation of transferrin receptor mRNA by IFN gamma.

IFN gamma inhibits the rise in transferrin receptor mRNA level which is normally observed when stationary WISH cells are stimulated to proliferate. This effect is not attributable to a change in the transcription rate of the transferrin receptor gene or in the cytoplasmic stability of the mRNA. The IFN gamma-induced reduction of the transferrin receptor mRNA content is already present at the nuclear level to an extent comparable to that observed in whole cells. Thus, IFN gamma does not impair the passage of this mRNA from the nuclear to the cytoplasmic compartment but probably interferes with a nuclear post-transcriptional event during the processing of the immature transferrin receptor mRNA. Two different levels of regulation of transferrin receptor mRNA have been previously reported. Iron modulates the cytoplasmic stability of this mRNA through the binding of a specific cytoplasmic factor, whereas cell growth variation influences the transcription of this gene. Our results suggest the existence of another mechanism of regulation for transferrin receptor gene expression not so far considered. Furthermore, the distinction between the mechanism of regulation exerted by IFN gamma and that exerted by cell proliferation on transferrin receptor gene expression suggests that, in WISH cells, the IFN-induced transferrin receptor decay is not a consequence of cell growth arrest but rather one of the causes of the antiproliferative effect of IFN through iron deprivation.

Blotting, Northern↗