Conditional down-regulation of GreA impacts expression of rRNA and transcription factors, affecting Mycobacterium smegmatis survival

Abstract The present study aimed to unravel the molecular basis underlying PAX3 down-regulation, known to be involved in pre-eclampsia (PE) occurrence and development. Data obtained from databases suggested that Pax3 methylation levels in the promoter region are high in the placentas of PE patients. However, the expression of methylation-adjusting enzymes, including DNMT1, LSD1, and EZH2, did not change. Since lncRNAs enhance the function of methylation-related enzymes independently of expression, we selected three lncRNAs, RP11-269F21.2, DIAPH2-AS1, and RP11-445K13.2, predicted to interact with methylation-adjusting enzymes. Two transcription factors, HOXD8 and Lhx3, predicted to regulate the expression of lncRNAs, were also selected. Using RNA interference technology, HOXD8 and Lhx3 were found to positively regulate DIAPH2-AS1 and RP11-445K13.2 in HTR-8/SVneo cells. Chromatin immunoprecipitation assays determined that DIAPH2-AS1 recruited LSD1 to histone 3, increasing DNMT1 stability at H3. The HOXD8/DIAPH2-AS1 network regulated HTR-8/SVneo cell function under hypoxia by epigenetically regulating PAX3. This regulatory network may thus be responsible for PAX3 down-regulation in the placentas of PE patients.

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C/EBPβ Is a Critical Factor for Proliferation and Apoptosis in MM Cells by Controlling Transcription Factors Like IRF-4, PAX5 and Blimp1.

Blood ◽

10.1182/blood.v110.11.1506.1506 ◽

2007 ◽

Vol 110 (11) ◽

pp. 1506-1506

Author(s):

Rekha Pal ◽

Martin Janz ◽

Deborah Galson ◽

Suzanne Lentzsch

Keyword(s):

Transcription Factors ◽

Western Blot ◽

Cell Lines ◽

Plasma Cells ◽

Annexin V ◽

Critical Factor ◽

Myeloma Cell ◽

Down Regulation ◽

Protein Levels ◽

Rpmi 8226

Abstract The development and maturation of plasma cells is dictated by multiple interacting transcription factors (TFs). C/EBPb (NF-IL6) is a TF regulated by IL-6 and has profound effects on the regulation of growth, survival and differentiation of B-cells. Mice deficient in C/EBPb show impaired generation of B lymphocytes suggesting that C/EBPb plays an important role in B lymphopoiesis. In this study we delineated the effect of C/EBPb on transcription factors critical for myeloma cell proliferation by over-expressing and inhibiting C/EBPb in myeloma cells. Multiple myeloma (MM) cell lines MM.1S, RPMI-8226 and H929 were transiently transfected with GFP, C/EBPb (pcNF-IL6), and truncated C/EBPb with a deletion of the internal spII-spII fragment [pcmNF-IL6(Dspl)] by using Bio-Rad Gene Pulser Xcell, followed by G418 selection. A pool of transfected cells was selected and subjected to thymidine incorporation, flow cytometry and western blot analysis. We found that transfection of a truncated form of C/EBPb induced a down-regulation of C/EBPb in MM cell lines (MM.1S, RPMI-8226 and H929) as measured by western blot. Down-regulation of C/EBPβ significantly inhibited proliferation and induced apoptosis of MM cell lines analyzed by annexin V-FITC/PI staining. This was accompanied by a complete down-regulation of the anti-apoptotic protein BCL-2. Further, inhibition of C/EBPb completely decreased IRF-4 expression. In contrast, over-expression of C/EBPb increased protein levels of IRF-4 suggesting that IRF-4 is under control of C/EBPb. IRF-4, which was over-expressed in all our tested MM cells lines, is an essential TF for the generation of plasma cells by regulating TFs like Blimp-1 and PAX-5, which are critical for plasma cell differentiation. Our studies showed that down-regulation of IRF-4 resulted in a complete abrogation of Blimp-1 and PAX-5 suggesting that the expression of these factors is C/EBPb/IRF-4 dependent. In conclusion, our data indicate that C/EBPb is an important key regulator for survival and growth of MM cells. We show for the first time that C/EBPb is a critical regulator upstream of IRF-4. Down-regulation of the C/EBPb and consequently IRF-4 results in complete disruption of the network of TFs necessary for MM growth and survival. Targeting C/EBPb may provide a novel therapeutic approach in the treatment of MM.

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Pax5 Activates Oncogenic Transcription Factors of the Ets Family by Repressing the mir-15a/16-1 microRNA Cluster.

Blood ◽

10.1182/blood.v110.11.346.346 ◽

2007 ◽

Vol 110 (11) ◽

pp. 346-346

Author(s):

Elaine Y. Chung ◽

Diana Cozma ◽

Duonan Yu ◽

Michael Dews ◽

Erik A. Wentzel ◽

...

Keyword(s):

Transcription Factors ◽

B Cell ◽

Western Blotting ◽

Cell Receptor ◽

Lymphocytic Leukemia ◽

Mrna Levels ◽

Down Regulation ◽

Protein Levels ◽

Ets Family ◽

Post Transcriptional Regulation

Abstract We have recently demonstrated that Pax5 promotes B-lymphomagenesis by upregulating key components of B-cell receptor signaling [Cozma et al, J Clin Inv, 117 (8), 2007]. Gene regulation by Pax5 often involves complex formation with other oncogenic transcription factors of the Ets family, namely Myb and Ets1. We determined that expression of these proteins themselves depends on the presence of Pax5, as seen in human diffuse large B-cell lymphomas with Pax5 knockdown and murine lymphomas with epigenetic silencing of Pax5 [Yu et al, Blood, 101:1950–1955, 2003; Johnson et al, Nat Immunol, 5:853–861, 2004]. Upon reconstitution with the Pax5 gene, Myb and Ets1 levels increase sharply. This occurs with little increase in steady-state mRNA levels, suggesting post-transcriptional regulation, possibly by microRNAs. To test this hypothesis, we compared miRNA profiles of Pax5-deficieint and sufficient cells and discovered that several miRNAs are indeed repressed by Pax5. Among them is the miR-15a/16-1 cluster whose predicted targets include both Myb and Ets1. Consistent with this prediction, forced expression of miR-15a/16 brings down Myb and Ets1 protein levels. This is accompanied by impaired Pax5 function and overall suppression of B-lymphomagenesis. Thus, Ets family members (along with previously identified bcl-2) are key targets of the miR-15a/16 locus, a tumor suppressor in chronic lymphocytic leukemia. Interplay between Pax5, Myb/Ets1, and miR-15a/16-1. (A) Upregulation of Myb and Ets 1 in tumors over-expressing Pax5ER fusion, as compared to control GFP-only neoplasms. (B) Down-regulation of Myb and Ets1 in Pax5 tumors engineered to over-express the miR-15a/16-1 cluster. All panels depict Western blotting. Interplay between Pax5, Myb/Ets1, and miR-15a/16-1. (A) Upregulation of Myb and Ets 1 in tumors over-expressing Pax5ER fusion, as compared to control GFP-only neoplasms. (B) Down-regulation of Myb and Ets1 in Pax5 tumors engineered to over-express the miR-15a/16-1 cluster. All panels depict Western blotting.

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Down-regulation of transcription factors by RNA interference. A novel approach to extend the multi-potency of autologous adult stem cells?

In Vitro Cellular & Developmental Biology - Animal ◽

10.1290/0405036 ◽

2004 ◽

Author(s):

Boon C. Heng ◽

Tong Cao

Keyword(s):

Stem Cells ◽

Transcription Factors ◽

Rna Interference ◽

Adult Stem Cells ◽

Regulation Of Transcription ◽

Down Regulation ◽

Novel Approach

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Transforming Growth Factor- 1 Down-Regulation of Major Histocompatibility Complex Class I in Thyrocytes: Coordinate Regulation Of Two Separate Elements by Thyroid-Specific as Well as Ubiquitous Transcription Factors

Molecular Endocrinology ◽

10.1210/me.14.4.486 ◽

2000 ◽

Vol 14 (4) ◽

pp. 486-505 ◽

Cited By ~ 8

Author(s):

G. Napolitano

Keyword(s):

Transcription Factors ◽

Major Histocompatibility Complex ◽

Growth Factor ◽

Major Histocompatibility Complex Class ◽

Transforming Growth Factor ◽

Class I ◽

Complex Class ◽

Down Regulation ◽

Coordinate Regulation ◽

Histocompatibility Complex

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Combined Loss of the GATA4 and GATA6 Transcription Factors in Male Mice Disrupts Testicular Development and Confers Adrenal-Like Function in the Testes

Endocrinology ◽

10.1210/en.2014-1907 ◽

2015 ◽

Vol 156 (5) ◽

pp. 1873-1886 ◽

Cited By ~ 29

Author(s):

Maria B. Padua ◽

Tianyu Jiang ◽

Deborah A. Morse ◽

Shawna C. Fox ◽

Heather M. Hatch ◽

...

Keyword(s):

Transcription Factors ◽

Double Mutant ◽

Immunohistochemical Analysis ◽

Side Chain ◽

Testicular Development ◽

Down Regulation ◽

Chain Cleavage ◽

Genes Encoding ◽

Cleavage Enzyme ◽

Steroidogenic Genes

The roles of the GATA4 and GATA6 transcription factors in testis development were examined by simultaneously ablating Gata4 and Gata6 with Sf1Cre (Nr5a1Cre). The deletion of both genes resulted in a striking testicular phenotype. Embryonic Sf1Cre; Gata4flox/flox Gata6flox/flox (conditional double mutant) testes were smaller than control organs and contained irregular testis cords and fewer gonocytes. Gene expression analysis revealed significant down-regulation of Dmrt1 and Mvh. Surprisingly, Amh expression was strongly up-regulated and remained high beyond postnatal day 7, when it is normally extinguished. Neither DMRT1 nor GATA1 was detected in the Sertoli cells of the mutant postnatal testes. Furthermore, the expression of the steroidogenic genes Star, Cyp11a1, Hsd3b1, and Hsd17b3 was low throughout embryogenesis. Immunohistochemical analysis revealed a prominent reduction in cytochrome P450 side-chain cleavage enzyme (CYP11A1)- and 3β-hydroxysteroid dehydrogenase-positive (3βHSD) cells, with few 17α-hydroxylase/17,20 lyase-positive (CYP17A1) cells present. In contrast, in postnatal Sf1Cre; Gata4flox/flox Gata6flox/flox testes, the expression of the steroidogenic markers Star, Cyp11a1, and Hsd3b6 was increased, but a dramatic down-regulation of Hsd17b3, which is required for testosterone synthesis, was observed. The genes encoding adrenal enzymes Cyp21a1, Cyp11b1, Cyp11b2, and Mcr2 were strongly up-regulated, and clusters containing numerous CYP21A2-positive cells were localized in the interstitium. These data suggest a lack of testis functionality, with a loss of normal steroidogenic testis function, concomitant with an expansion of the adrenal-like cell population in postnatal conditional double mutant testes. Sf1Cre; Gata4flox/flox Gata6flox/flox animals of both sexes lack adrenal glands; however, despite this deficiency, males are viable in contrast to the females of the same genotype, which die shortly after birth.

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