A novel, erythroid cell-specific murine transcription factor that binds to the CACCC element and is related to the Krüppel family of nuclear proteins

1993 ◽  
Vol 13 (5) ◽  
pp. 2776-2786 ◽  
Author(s):  
I J Miller ◽  
J J Bieker
Keyword(s):  
Dna Binding ◽  
Cell Line ◽  
Cell Lines ◽  
Zinc Fingers ◽  
Essential Element ◽  
Tissue Expression ◽  
Erythroid Cell ◽  
Cell Phenotype ◽  
Erythroleukemia Cell ◽  
Globin Promoter

We describe a novel erythroid cell-specific cDNA (EKLF [erythroid Krüppel-like factor]) isolated by enriching for genes expressed in a mouse erythroleukemia cell line but not expressed in a mouse monocyte-macrophage cell line. The complete cDNA sequence is predicted to encode a protein of approximately 38,000 Da that contains a proline-rich amino domain and three TFIIIA-like zinc fingers within the carboxy domain. Additional sequence analyses reveal that the EKLF zinc fingers are most homologous to the Krüppel family of transcription factors and also allow us to predict potential DNA-binding target sites for the EKLF protein. On the basis of this prediction, we show that EKLF is able to bind the sequence CCA CAC CCT, an essential element of the beta-globin promoter. Its tissue distribution establishes that the EKLF transcript is expressed only in bone marrow and spleen, the two hematopoietic organs of the mouse, and analysis of murine cell lines indicates that EKLF expression is limited to erythroid and mast cell lines. Cotransfection assays establish that EKLF transcriptionally activates a target promoter that contains its DNA-binding site. The tissue expression pattern of EKLF, in conjunction with its function as a transcriptional activator, strongly suggests that the EKLF protein may be intimately involved in establishment and/or maintenance of the erythroid cell phenotype.

scholarly journals A novel, erythroid cell-specific murine transcription factor that binds to the CACCC element and is related to the Krüppel family of nuclear proteins.

1993 ◽  
Vol 13 (5) ◽  
pp. 2776-2786 ◽  
Author(s):  
I J Miller ◽  
J J Bieker
Keyword(s):  
Dna Binding ◽  
Cell Line ◽  
Cell Lines ◽  
Zinc Fingers ◽  
Essential Element ◽  
Tissue Expression ◽  
Erythroid Cell ◽  
Cell Phenotype ◽  
Erythroleukemia Cell ◽  
Globin Promoter

We describe a novel erythroid cell-specific cDNA (EKLF [erythroid Krüppel-like factor]) isolated by enriching for genes expressed in a mouse erythroleukemia cell line but not expressed in a mouse monocyte-macrophage cell line. The complete cDNA sequence is predicted to encode a protein of approximately 38,000 Da that contains a proline-rich amino domain and three TFIIIA-like zinc fingers within the carboxy domain. Additional sequence analyses reveal that the EKLF zinc fingers are most homologous to the Krüppel family of transcription factors and also allow us to predict potential DNA-binding target sites for the EKLF protein. On the basis of this prediction, we show that EKLF is able to bind the sequence CCA CAC CCT, an essential element of the beta-globin promoter. Its tissue distribution establishes that the EKLF transcript is expressed only in bone marrow and spleen, the two hematopoietic organs of the mouse, and analysis of murine cell lines indicates that EKLF expression is limited to erythroid and mast cell lines. Cotransfection assays establish that EKLF transcriptionally activates a target promoter that contains its DNA-binding site. The tissue expression pattern of EKLF, in conjunction with its function as a transcriptional activator, strongly suggests that the EKLF protein may be intimately involved in establishment and/or maintenance of the erythroid cell phenotype.

Suppression of albumin enhancer activity by H-ras and AP-1 in hepatocyte cell lines

1994 ◽  
Vol 14 (3) ◽  
pp. 1531-1543
Author(s):  
J Hu ◽  
H C Isom
Keyword(s):  
Dna Binding ◽  
Cell Line ◽  
Cell Lines ◽  
Binding Sites ◽  
Simian Virus 40 ◽  
Site Directed Mutagenesis ◽  
Ras Signaling ◽  
Enhancer Activity ◽  
Hepatocyte Cell Line ◽  
Transformed Cell Lines

We demonstrated, using a transient transfection assay, that the albumin enhancer increased the expression of the albumin promoter in a highly differentiated, simian virus 40 (SV40)-immortalized hepatocyte cell line, CWSV1, but was not functional in two ras-transformed cell lines (NR3 and NR4) derived from CWSV1 by stable transfection with the T24ras oncogene. A transient cotransfection assay showed that T24ras and normal c-Ha-ras were each able to inhibit the activity of the albumin enhancer in an immortal hepatocyte cell line. DNase I footprinting and gel mobility shift assays demonstrated that the DNA binding activities specific to the albumin enhancer were not decreased in the ras-transformed cells. ras also did not diminish the expression of HNF1 alpha, C/EBP alpha, HNF3 alpha, HNF3 beta, or HNF3 gamma but did significantly increase AP-1 binding activity. Three AP-1 binding sites were identified within the albumin enhancer, and DNA binding activities specific to these AP-1 sites were induced in the ras-transformed hepatocytes. Subsequent functional assays showed that overexpression of c-jun and c-fos inhibited the activity of the albumin enhancer. Site-directed mutagenesis of the AP-1 binding sites in the albumin enhancer partially abrogated the suppressing effect of ras and c-jun/c-fos on the enhancer. These functional studies therefore supported the results of the structural studies with AP-1. We conclude that the activity of the albumin enhancer is subject to regulation by ras signaling pathways and that the effect of ras on the albumin enhancer activity may be mediated by AP-1.

scholarly journals Spontaneous delta- to beta-globin switching in K562 human leukemia cells

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 820-825 ◽  
Author(s):  
B Mookerjee ◽  
MO Arcasoy ◽  
GF Atweh
Keyword(s):  
Cell Line ◽  
Messenger Rna ◽  
Culture Conditions ◽  
Human Leukemia ◽  
Globin Genes ◽  
Beta Globin ◽  
Globin Mrna ◽  
Hemoglobin Switching ◽  
Erythroleukemia Cell ◽  
Globin Promoter

Abstract Previous analysis of the hemoglobin phenotype of the K562 human erythroleukemia cell line showed regulated expression of the epsilon-, zeta-, gamma-, alpha-, and delta-globin genes. Expression of the beta- globin genes has not been previously detected in this cell line. In this report, we describe the isolation of a variant of the K562 cell line that actively expresses beta-globin messenger RNA (mRNA) and polypeptide and shows greatly reduced expression of the delta-globin genes. This phenotype developed spontaneously in culture while two other K562 isolates grown under the same culture conditions have not undergone the same delta- to beta-globin switch. Analysis of this unique K562 variant shows that a construct containing a beta-globin promoter is quite active upon transient transfection into these cells. This finding suggests that the activation of the endogenous beta-globin genes results from changes in the trans-acting environment of these cells. The regulation of the beta-globin genes in this variant is characterized by a paradoxical decrease in the level of beta-globin mRNA after exposure to hemin. Other globin genes of this variant are appropriately regulated and show increased expression after hemin induction. Further study of this variant may shed light on mechanisms of gene regulation that are involved in hemoglobin switching.

Microrna Expression Profiling in Acute Myelogenous Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1131-1131
Author(s):  
Fernando J. Suarez Saiz ◽  
Serban San-Marina ◽  
Mark D. Minden
Keyword(s):  
Bone Marrow ◽  
Cell Line ◽  
Cell Lines ◽  
Acute Myelogenous Leukemia ◽  
Myelogenous Leukemia ◽  
Erythroid Cell ◽  
Normal Bone Marrow ◽  
Hematopoietic Differentiation ◽  
Normal Bone ◽  
Acute Myelogenous

Abstract Acute myelogenous leukemia (AML) arises due to changes in gene expression that block or alter the normal differentiation program of hematopoietic stem cells. A variety of mutations in protein-encoding genes have been shown to contribute to the development of leukemia. Recently a new class of genes called microRNAs (miRNAs) have been identified. miRNAs are a subgroup of highly conserved, non-coding RNAs found only in eukaryotes. They do not encode proteins, and appear to have a significant effect on the proteome of a cell. Their conservation between species suggests their involvement in important biological functions, and in fact been shown to be involved in hematopoietic differentiation. While the function of most miRNAs is still unknown, it is believed that they regulate expression of target mRNAs by using the siRNA machinery either to promote degradation of the mRNA or to block its translation. To begin to understand the role of miRNAs in AML, we used Quantitative Polymerase Chain Reaction (QPCR) to measure the expression level of 20 miRNA precursors in the pro erythroid cell line K562, the pro-myelocytic cell line NB4, the myelomococytic cell line OCI/AML2, AML patients’ blasts and in normal bone marrow (NBM). The investigated miRNAs included some that are known to be specific for hematopoietic tissues or involved in hematopoietic differentiation, as well as all the miRNAs in chromosome 7, a hot spot for gene deletion in AML. Our findings indicate that miRNAs are differentially expressed in patients and cell lines when compared among themselves and against normal bone marrow. For example pre-miR-142 was expressed in NBM and K562 but was found to be elevated in OCI/AML2, NB4 and in all patient samples. Pre-miR-20 was found to be overexpressed in only a subset of patients. Other miRNAs like pre-miR-335 and pre-miR-148a were expressed in NBM and in some patients and not in the cell lines. In an effort to identify possible regulators of miRNA expression, we analyzed the upstream region of pre-miR-142 and found an LMO2 binding site. In AML, the LMO2 gene can be overexpressed relative to normal bone marrow and healthy lymphocytes. This transcription factor is involved in the regulation of genes important in the development of blood cells. To investigate if LMO2 could be involved in the regulation of miR-142 expression, we performed chromatin immunoprecipitation (ChIP) from K562 using an anti-LMO2 antibody. Only the LMO2 immunoprecipitation, and not those from the pre-immune control, were enriched in promoter DNA for pre-miR-142. This is consistent with the observation that miRNAs and coding RNAs can be regulated by the same environmental signals. Based on this observation we propose that oncogenes regulate in part the phenotype and biological behaviour of leukemia by affecting the expression of miRNAs. This further suggests that different forms of leukemia may be recognized based upon the spectrum of miRNAs they express.

Lack of PRDM1α Expression in Hodgkin/Reed-Sternberg Cells Is Likely Mediated by a Translational or Post-Translational Mechanism.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4367-4367
Author(s):  
Wayne Tam ◽  
Leonard Tan ◽  
Mario Gomez ◽  
Shaoan Fan ◽  
Yifang Liu ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cell ◽  
Cell Line ◽  
Cell Fate ◽  
Cell Lines ◽  
Western Blotting ◽  
Plasma Cell ◽  
Zinc Finger Protein ◽  
Cell Phenotype

Abstract Hodgkin/Reed Sternberg (H/RS) cells are the neoplastic cells in classical Hodgkin lymphoma (HL). They are thought to resemble post-germinal center (GC) B cells with expression of markers associated with late stage of B-cell differentiation, for example, interferon regulatory factor -4/multiple myeloma-1 (IRF4/MUM1) and syndecan 1 (CD138). The PR (PRDI-BF1-RIZ) domain zinc finger protein 1 (PRDM1), a transcription repressor with a master regulatory role in plasma cell differentiation, is normally co-expressed with IRF-4/MUM-1 in plasma cells and in a subset of activated GC cells committed to plasma cell fate. We studied expression of PRDM1α, the functional isoform of PRDM1, in 14 classical HL cases [including 3 positive for Epstein-Barr-virus (EBV)] and 4 HL cell lines by immunohistochemistry and Western blotting, respectively. H/RS cells in primary HL cases are negative for PRDM1α, implying a desynchrony in expression between IRF-4/MUM1 and PRDM1. While the myeloma cell line U266 expresses relatively abundant PRDM1α, it was undetectable by Western Blotting in all HL cell lines tested, except for the EBV-positive HL cell line L591 which, unlike in vivo H/RS cells, has a Type III EBV latency pattern. PRDM1α expression in L591 but not in vivo H/RS cells suggests that PRDM1 expression may be modulated by latency type-specific EBV-encoded gene products or the B-cell phenotype exhibited by the cell line. The lack of PRDM1α protein in H/RS cells is not due to impaired gene transcription, since real-time quantitative PCR revealed similarly abundant PRDM1α transcripts in the HL cell lines as U266. In the absence of mutation in the PRDM1 coding region, these results suggest that failure to accumulate PRDM1α protein in H/RS cells is likely due to abnormal translation repression or protein turnover. Loss of functional PRDM1 as a result of translational or post-translational deregulation may represent a novel molecular lesion in HL.

Differential Modulation of the β-Like Globin Genes by KLFs Isolated with a γ-Globin CACCC Bait.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3637-3637
Author(s):  
Paolo Moi ◽  
Loredana Porcu ◽  
Maria G. Marini ◽  
Isadora Asunis ◽  
Maria G. Loi ◽  
...  
Keyword(s):  
Cell Lines ◽  
Globin Gene ◽  
K562 Cells ◽  
Tissue Expression ◽  
Pcr Analysis ◽  
Globin Genes ◽  
Band Shift ◽  
Hemoglobin Switching ◽  
Specific Complex ◽  
Globin Promoter

Abstract The globin CACCC boxes are absolutely required for the appropriate regulation of the β-like globin genes. While the β-globin CACCC box binds EKLF/KLF1, a likely adult switching factor, analogous factors, interacting with the γ-globin gene and predicted to regulate the fetal stage of hemoglobin switching, have so far been elusive. By using yeast one hybrid assay, we have isolated four KLFs, KLF1, 2, 4, and 6, that bound the γ-CACCC bait. To establish their role in globin regulation and in the switching of hemoglobins, these factors were compared to four other KLFs already established or putative globin regulators, KLF3, 11, 13 and 16, mainly evaluating their ability to bind and transactivate the ε-, γ- and β-globin gene. γ-CACCC binding at variable intensities was confirmed in band shift assay for all four isolated KLFs, for KLF3 and, faintly, for KLF13. The ε- and β-CACCC were bound by the same factors with similar affinities with the exception of KLF3 and KLF13 that bound stronger to the β- and ε- than to the γ-CACCC box. On the other hand, KLF11 and 16 did not produce any specific complex in band shift assays with anyone of the globin CACCC boxes. More relevant differences were observed among the factors in the transactivation of single and dual luciferase reporters in both K562 and MEL cells. In these assays, most factors presented peculiar modulatory properties and specific promoter tropism. Several factors presented bidirectional activity displaying in the same time the capacity to stimulate and repress different globin promoters. KLF1 and 4 were the strongest stimulators of the β-globin promoter in both cell lines, whereas KLF2 activated the β-promoter only in K562 cells. KLF1 and especially KLF4 consistently repressed ε-globin expression especially in MEL cells. KLF3 behaved always as a general globin repressor in MEL cells, but acted as a weak stimulator of the γ- and ε-promoter in K562 cells. KLF4 was the strongest inhibitor of the ε-globin gene. KLF13 significantly stimulated the γ-promoter in both cell lines, whereas KLF3, 4 and 6 showed statistically significant stimulation only in MEL cells. By RT-PCR analysis we found that KLFs were highly variable in their tissue expression and that KLF1, 3 and 13 had the highest expression in erythroid tissues. Thus the level of tissue expression should ultimately determine which factors are really active in physiological conditions. Taken together our binding and expression studies suggest that several KLFs have the potential to modulate the activity of the globin genes and that the resulting globin expression will depend on the vectorial sum of the relative activities of the factors expressed at any given time of development. Furthermore, as some KLFs, like KLF1 and 4, exert opposite effects on fetal and adult globin genes, their role in hemoglobin switching may be direct and not only dependent on their ability to mediate promoter competition for the LCR.

scholarly journals Spontaneous delta- to beta-globin switching in K562 human leukemia cells

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 820-825
Author(s):  
B Mookerjee ◽  
MO Arcasoy ◽  
GF Atweh
Keyword(s):  
Cell Line ◽  
Messenger Rna ◽  
Culture Conditions ◽  
Human Leukemia ◽  
Globin Genes ◽  
Beta Globin ◽  
Globin Mrna ◽  
Hemoglobin Switching ◽  
Erythroleukemia Cell ◽  
Globin Promoter

Previous analysis of the hemoglobin phenotype of the K562 human erythroleukemia cell line showed regulated expression of the epsilon-, zeta-, gamma-, alpha-, and delta-globin genes. Expression of the beta- globin genes has not been previously detected in this cell line. In this report, we describe the isolation of a variant of the K562 cell line that actively expresses beta-globin messenger RNA (mRNA) and polypeptide and shows greatly reduced expression of the delta-globin genes. This phenotype developed spontaneously in culture while two other K562 isolates grown under the same culture conditions have not undergone the same delta- to beta-globin switch. Analysis of this unique K562 variant shows that a construct containing a beta-globin promoter is quite active upon transient transfection into these cells. This finding suggests that the activation of the endogenous beta-globin genes results from changes in the trans-acting environment of these cells. The regulation of the beta-globin genes in this variant is characterized by a paradoxical decrease in the level of beta-globin mRNA after exposure to hemin. Other globin genes of this variant are appropriately regulated and show increased expression after hemin induction. Further study of this variant may shed light on mechanisms of gene regulation that are involved in hemoglobin switching.

Charcterization of a Newly Established Megakaryo/Erythroid Leukemia Cell Line, JAS-R.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4327-4327
Author(s):  
Hisashi Yamada ◽  
Junko Horiguchi-Yamada ◽  
Tetsuaki Sekikawa
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Leukemia Cell ◽  
Leukemic Cell ◽  
Neutralizing Antibody ◽  
Chromosome Analysis ◽  
Erythropoietin Receptor ◽  
Leukemia Cell Line ◽  
Erythroid Cell ◽  
Leukemic Cell Lines

Abstract A few leukemic cell lines which express megakaryo/erythroid markers are available. We recently established a new cell line, designated JAS-R, from a 64-year-old patient with acute megakaryocytic leukemia (AML M7). Immunophenotyping showed that JAS-R cells were positive for CD4, CD7, CD13, CD33, CD41, CD61 and glycophorin A. Chromosome analysis was composite karyotype, but no major translocation abnormalities were observed. Electron-microscope examination disclosed that JAS-R had bleb like surface margin and a-granules in cytoplasm. Major four proteins which exist in a-granule were expressed high levels in JAS-R by RT-PCR. To further characterize JAS-R from four other megakaryo/erythroid cell lines (MEG-01, CMK, K562 and KU812), the comparison of gene expression profiling was studied by using oligo-DNA array. JAS-R was categorized as most different cell line among them. Of note, JAS-R secreted erythropoietin and expressed erythropoietin-receptor. But erythropoietin-neutralizing antibody failed to inhibit the growth of JAS-R cells. JAS-R may be useful for the further understanding of megakaryo and erythroid regulation and for the study of megakaryo/erythroid leukemogenesis.

Deep Mining of Natural Genetic Variation in Erythroid Cells Reveals New Insights about In Vivo Transcription Factor Binding and Chromatin Accessibility

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3879-3879
Author(s):  
Vivek Behera ◽  
Perry Evans ◽  
Carolyne J Face ◽  
Laavanya Sankaranarayanan ◽  
Gerd A. Blobel
Keyword(s):  
Transcription Factor ◽  
Genetic Variation ◽  
Transcription Factors ◽  
Cell Line ◽  
Cell Lines ◽  
Genetic Variants ◽  
Binding Sites ◽  
Chromatin Accessibility ◽  
Erythroid Cell

Abstract Erythroid transcription factors (TFs) control gene expression programs, lineage decisions, and disease outcomes. How transcription factors contact DNA has been studied extensively in vitro, but in vivo binding characteristics are less well understood as they are influenced in a reciprocal manner by chromatin accessibility and neighboring transcription factors. Here, we present a comparative analysis approach that takes advantage of non-coding sequence variation between functionally equivalent erythroid cell lines to conduct an in-depth analysis of erythroid TF binding profiles and chromatin features. Specifically, we analyzed ChIP-seq datasets to identify millions of genetic non-coding variants between the mouse erythroleukemia cell line (MEL), a GATA1-inducible erythroid progenitor cell line (G1E-ER4), and primary murine erythroblast cells. We found that while these cell lines are highly positively correlated in chromatin features, larger differences in TF binding intensity are correlated with higher degrees of genetic variation between cell lines. We next examined discriminatory genetic variants between the cell lines that are located in ChIP-seq peaks of the erythroid transcription factor GATA1. Hundreds of such variants fall within GATA1 motifs. Differential GATA1 binding intensities associated with the variants revealed nucleotide positions that contribute most to in vivo GATA1 chromatin occupancy and identified which alternative nucleotides are most likely to disrupt binding. Notably, this additional information about GATA1's in vivo nucleotide binding preferences improved prediction of GATA1 binding sites genome-wide. We applied similar approaches to determine the bp-resolution in vivo binding preferences of TAL1/SCL and CTCF. We additionally identified thousands of discriminatory genetic variants within GATA1 sites that fall outside canonical GATA elements but within binding sites of other known TFs. Association of these variants with differential GATA1 binding intensities revealed that the hematopoietic transcription factors TAL1/SCL and KLF1 positively regulate GATA1 chromatin occupancy. Strikingly, we identified a number of motifs not previously implicated in cooperating with GATA1 that positively impact GATA1 chromatin binding. Notably, we also defined motifs associated with negative regulation of GATA1 chromatin occupancy. Applying a similar analysis to TAL1/SCL and CTCF revealed additional motifs involved in regulating the chromatin occupancy of these TFs. Finally, we associated discriminatory genetic variation between erythroid cell lines with large changes in sub-kb-scale DNase hypersensitivity. We found that single base pair substitutions within or near a number of erythroid TF motifs, including that for the RUNX family of nuclear factors, are strongly associated with changes in chromatin accessibility. Our findings use novel methods in comparative ChIP-seq and DNase-seq analysis to reveal new insights about the genetic basis for erythroid TF chromatin occupancy and chromatin accessibility. Disclosures No relevant conflicts of interest to declare.

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