Pituitary Homeobox 1 Activates the Rat FSHβ (rFSHβ) Gene through Both Direct and Indirect Interactions with the rFSHβ Gene Promoter

Abstract Molecular mechanisms underlying gonadotrope-specific and hormonal regulation of FSHβ gene expression remain largely unknown. We have studied the role of pituitary homeobox 1 (Ptx1), a transcription factor important for regulation of many pituitary-specific genes, in the regulation of rat FSHβ (rFSHβ) gene transcription. We demonstrate that Ptx1 activates the rFSHβ gene promoter both basally and in synergy with GnRH. The effect of Ptx1 was localized to −140/−50, a region also important for basal activity of the promoter. Two putative Ptx1 binding sites (P1 and P2) homologous to consensus Ptx1 binding elements were identified in this region. We demonstrate specific binding of Ptx1 to the P2 but not to the P1 site. Furthermore, functional studies indicate that the P2 but not the P1 site mediates activation of the promoter by Ptx1. Residual activation of the promoter by Ptx1 was observed independent of the P2 site. However, no additional Ptx1 binding sites were identified in this region, indicating that the residual activation observed is likely independent of direct Ptx1 binding to the promoter. These results identify a functional Ptx1 binding site in the rFSHβ gene promoter and suggest the presence of an additional activating pathway that is independent of direct binding of Ptx1 to the promoter.

Download Full-text

A Ras-LSD1 axis activates PI3K signaling through PIK3IP1 suppression

Oncogenesis ◽

10.1038/s41389-019-0185-4 ◽

2020 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Kyunghee Lee ◽

Mayumi Kitagawa ◽

Pei Ju Liao ◽

David M. Virshup ◽

Sang Hyun Lee

Keyword(s):

Gene Expression ◽

Cancer Cells ◽

Molecular Mechanisms ◽

Gene Promoter ◽

Pi3k Pathway ◽

Pi3k Signaling ◽

Interacting Protein ◽

Lysine Specific Demethylase ◽

Ras Activation

AbstractPI3K Interacting Protein 1 (PIK3IP1) is a suppressor of the PI3K/Akt/mTOR pathway. We previously reported that activated Ras suppresses PIK3IP1 expression to positively regulate the PI3K pathway in cancer cells. Using doxycycline-inducible PIK3IP1, here we confirm that reversing the effect of Ras by inducing expression of PIK3IP1 suppresses Ras-induced anchorage-independent growth, supporting the central role of PIK3IP1 in transformation. However, the molecular mechanisms by which Ras-activation that causes loss of PIK3IP1 expression are unknown. We find that Ras activity represses PIK3IP1 expression via the recruitment of lysine-specific demethylase 1 (LSD1) to the PIK3IP1 gene promoter and enhancer, resulting in erasure of active histone marks. These studies demonstrate cross-activation of Ras/Raf/MEK/ERK and PI3K/AKT/mTOR pathways, where Ras decommissions PIK3IP1 gene expression by enhancing LSD1 and its corepressor activities to suppress PIK3IP1 transcription.

Download Full-text

The Role of Translation Initiation Regulation in Haematopoiesis

Comparative and Functional Genomics ◽

10.1155/2012/576540 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Godfrey Grech ◽

Marieke von Lindern

Keyword(s):

Gene Expression ◽

Translation Initiation ◽

Translational Control ◽

Molecular Mechanisms ◽

Rna Binding ◽

Regulation Of Gene Expression ◽

Mrna Translation ◽

Translation Control ◽

Haematological Disorders

Organisation of RNAs into functional subgroups that are translated in response to extrinsic and intrinsic factors underlines a relatively unexplored gene expression modulation that drives cell fate in the same manner as regulation of the transcriptome by transcription factors. Recent studies on the molecular mechanisms of inflammatory responses and haematological disorders indicate clearly that the regulation of mRNA translation at the level of translation initiation, mRNA stability, and protein isoform synthesis is implicated in the tight regulation of gene expression. This paper outlines how these posttranscriptional control mechanisms, including control at the level of translation initiation factors and the role of RNA binding proteins, affect hematopoiesis. The clinical relevance of these mechanisms in haematological disorders indicates clearly the potential therapeutic implications and the need of molecular tools that allow measurement at the level of translational control. Although the importance of miRNAs in translation control is well recognised and studied extensively, this paper will exclude detailed account of this level of control.

Download Full-text

Trans-activation of the human SOX3 promoter by MAZ in NT2/D1 cells

Archives of Biological Sciences ◽

10.2298/abs0803379k ◽

2008 ◽

Vol 60 (3) ◽

pp. 379-387 ◽

Cited By ~ 2

Author(s):

Natasa Kovacevic-Grujicic ◽

Kazunari Yokoyama ◽

Milena Stevanovic

Keyword(s):

Gene Expression ◽

Neuronal Differentiation ◽

Gene Transcription ◽

Binding Sites ◽

Promoter Activity ◽

Zinc Finger Protein ◽

Mobility Shift ◽

Finger Protein ◽

Sox3 Gene

In this study, we examine the role of three highly conserved putative binding sites for Myc-associated zinc finger protein (MAZ) in regulation of the human SOX3 gene expression. Electrophoretic mobility shift and supershift assays indicate that complexes formed at two out of three MAZ sites of the human SOX3 promoter involve ubiquitously expressed MAZ protein. Furthermore, in cotransfection experiments we demonstrate that MAZ acts as a positive regulator of SOX3 gene transcription in both undifferentiated and RA-differentiated NT2/D1 cells. Although MAZ increased both basal and RA-induced promoter activity, our results suggest that MAZ does not contribute to RA inducibility of the SOX3 promoter during neuronal differentiation of NT2/D1 cells.

Download Full-text

Abstract O-1: Klf5 Regulates Cardiac Pparα and Med13 and affects Cardiac Fatty Acid Metabolism And Obesity

Circulation Research ◽

10.1161/res.115.suppl_1.o-1 ◽

2014 ◽

Vol 115 (suppl_1) ◽

Author(s):

Konstantinos Drosatos ◽

Nina Pollak ◽

Panagiotis Ntziachristos ◽

Chad M Trent ◽

Yunying Hu ◽

...

Keyword(s):

Gene Expression ◽

Fatty Acid ◽

Fatty Acid Metabolism ◽

Binding Sites ◽

Transcription Initiation ◽

Acid Metabolism ◽

Gene Promoter ◽

Initiation Site ◽

White Adipocytes ◽

Metabolic Role

Krüppel-like factors (KLF) have been associated with metabolic phenotypes. Our study focused on the metabolic role of cardiac KLF5, as it showed the highest increase among all KLFs that were detected by whole genome microarrays of energy-starved hearts obtained from lipopolysaccharide (LPS)-treated mice. Analysis of ppara promoter indicated two potential binding sites for c-Jun (AP-1 sites), the transcriptional factor that is activated by LPS and reduces cardiac PPARα expression: −792/-772 bp and −719/-698 bp prior to the transcription initiation site. This analysis showed that both AP-1 sites overlap with potential KLF-binding sites. Adenovirus-mediated expression of constitutively active c-Jun in a mouse cardiomyocyte cell line (HL-1) reduced PPARα gene expression, while treatment with Ad-KLF5 had the opposite effect. Chromatin immunoprecipitation analysis (ChIP) showed that c-Jun binds both −792/-772 bp and −719/-698 sites of ppara promoter while KLF5 binds on −792/-772 bp. ChIP analysis also showed that LPS promotes c-Jun binding on −792/-772 bp, which prohibits occupation of this region by KLF5. A cardiomyocyte-specific KLF5 knockout mouse (αMHC-KLF5-/-) had normal cardiac function but reduced cardiac expression of PPARα (50%) and other fatty acid metabolism-associated genes such as CD36 (40%), LpL (20%), PGC1α (45%), AOX (28%) and Cpt1 (45%). High fat diet (HFD)-fed αMHC-KLF5-/- mice had a more profound body weight increase (35%) compared to HFD-fed WT mice (15%), as well as larger white adipocytes and brown adipocytes (H&E) and increased hepatic neutral lipid accumulation (Oil-Red-O). The obesogenic effect of cardiomyocyte-specific deletion of KLF5 resembles the phenotype of the αMHC-MED13-/- mice. We showed that KLF5 ablation reduced cardiac MED13 levels despite lack of changes in the expression levels of miR-208, a known regulator of MED13. Infection of HL-1 cells with Ad-KLF5 increased MED13 gene expression. ChIP identified a KLF5 binding site on med13 gene promoter region (-730/-714 bp). Thus, KLF5 regulates cardiac PPARα and MED13 and affects cardiac and systemic fatty acid metabolism and obesity, thus indicating KLF5 as a potential target for cardiac dysfunction associated with energetic complications, as well as for obesity

Download Full-text

Isolation and functional characterization of Spirulina D6D gene promoter: Role of a putative GntR transcription factor in transcriptional regulation of D6D gene expression

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2007.11.018 ◽

2008 ◽

Vol 365 (4) ◽

pp. 643-649 ◽

Cited By ~ 10

Author(s):

Sanjukta Subudhi ◽

Pavinee Kurdrid ◽

Apiradee Hongsthong ◽

Matura Sirijuntarut ◽

Supapon Cheevadhanarak ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Transcriptional Regulation ◽

Functional Characterization ◽

Gene Promoter

Download Full-text

Phorbol Ester-Induced Human Cytomegalovirus Major Immediate-Early (MIE) Enhancer Activation through PKC-Delta, CREB, and NF-κB Desilences MIE Gene Expression in Quiescently Infected Human Pluripotent NTera2 Cells

Journal of Virology ◽

10.1128/jvi.00416-10 ◽

2010 ◽

Vol 84 (17) ◽

pp. 8495-8508 ◽

Cited By ~ 22

Author(s):

Xiaoqiu Liu ◽

Jinxiang Yuan ◽

Allen W. Wu ◽

Patrick W. McGonagill ◽

Courtney S. Galle ◽

...

Keyword(s):

Gene Expression ◽

Human Cytomegalovirus ◽

Binding Sites ◽

Molecular Mechanisms ◽

Cell Model ◽

Gene Activation ◽

Dominant Negative ◽

Immediate Early ◽

Signaling Cascade ◽

Pkc Delta

ABSTRACT The ways in which human cytomegalovirus (HCMV) major immediate-early (MIE) gene expression breaks silence from latency to initiate the viral replicative cycle are poorly understood. A delineation of the signaling cascades that desilence the HCMV MIE genes during viral quiescence in the human pluripotent N-Tera2 (NT2) cell model provides insight into the molecular mechanisms underlying HCMV reactivation. In this model, we show that phorbol 12-myristate 13-acetate (PMA) immediately activates the expression of HCMV MIE RNA and protein and greatly increases the MIE-positive (MIE+) NT2 cell population density; levels of Oct4 (pluripotent cell marker) and HCMV genome penetration are unchanged. Decreasing PKC-delta activity (pharmacological, dominant-negative, or RNA interference [RNAi] method) attenuates PMA-activated MIE gene expression. MIE gene activation coincides with PKC-delta Thr505 phosphorylation. Mutations in MIE enhancer binding sites for either CREB (cyclic AMP [cAMP] response element [CRE]) or NF-κB (κB) partially block PMA-activated MIE gene expression; the ETS binding site is negligibly involved, and κB does not confer MIE gene activation by vasoactive intestinal peptide (VIP). The PMA response is also partially attenuated by the RNAi-mediated depletion of the CREB or NF-κB subunit RelA or p50; it is not diminished by TORC2 knockdown or accompanied by TORC2 dephosphorylation. Mutations in both CRE and κB fully abolish PMA-activated MIE gene expression. Thus, PMA stimulates a PKC-delta-dependent, TORC2-independent signaling cascade that acts through cellular CREB and NF-κB, as well as their cognate binding sites in the MIE enhancer, to immediately desilence HCMV MIE genes. This signaling cascade is distinctly different from that elicited by VIP.

Download Full-text

Direct and widespread role for the nuclear receptor EcR in mediating the response to ecdysone in Drosophila

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1900343116 ◽

2019 ◽

Vol 116 (20) ◽

pp. 9893-9902 ◽

Cited By ~ 14

Author(s):

Christopher M. Uyehara ◽

Daniel J. McKay

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Nuclear Receptor ◽

Binding Sites ◽

Transcriptional Responses ◽

Enhancer Activity ◽

Developmental Transitions ◽

Experimental Systems ◽

The Impact

The ecdysone pathway was among the first experimental systems employed to study the impact of steroid hormones on the genome. In Drosophila and other insects, ecdysone coordinates developmental transitions, including wholesale transformation of the larva into the adult during metamorphosis. Like other hormones, ecdysone controls gene expression through a nuclear receptor, which functions as a ligand-dependent transcription factor. Although it is clear that ecdysone elicits distinct transcriptional responses within its different target tissues, the role of its receptor, EcR, in regulating target gene expression is incompletely understood. In particular, EcR initiates a cascade of transcription factor expression in response to ecdysone, making it unclear which ecdysone-responsive genes are direct EcR targets. Here, we use the larval-to-prepupal transition of developing wings to examine the role of EcR in gene regulation. Genome-wide DNA binding profiles reveal that EcR exhibits widespread binding across the genome, including at many canonical ecdysone response genes. However, the majority of its binding sites reside at genes with wing-specific functions. We also find that EcR binding is temporally dynamic, with thousands of binding sites changing over time. RNA-seq reveals that EcR acts as both a temporal gate to block precocious entry to the next developmental stage as well as a temporal trigger to promote the subsequent program. Finally, transgenic reporter analysis indicates that EcR regulates not only temporal changes in target enhancer activity but also spatial patterns. Together, these studies define EcR as a multipurpose, direct regulator of gene expression, greatly expanding its role in coordinating developmental transitions.

Download Full-text

Pituitary transcription factor Prop-1 stimulates porcine pituitary glycoprotein hormone α subunit gene expression

Journal of Molecular Endocrinology ◽

10.1677/jme.1.02010 ◽

2006 ◽

Vol 37 (2) ◽

pp. 341-352 ◽

Cited By ~ 14

Author(s):

Takanobu Sato ◽

Kousuke Kitahara ◽

Takao Susa ◽

Takako Kato ◽

Yukio Kato

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Binding Sites ◽

Gh3 Cells ◽

Pituitary Hormone ◽

Transcriptional Level ◽

Β Subunit ◽

Glycoprotein Hormone ◽

Α Subunit

Recently, we have reported that a Prophet of Pit-1 homeodomain factor, Prop-1, is a novel transcription factor for the porcine follicle-stimulating hormone β subunit (FSHβ) gene. This study subsequently aimed to examine the role of Prop-1 in the gene expression of two other porcine gonadotropin subunits, pituitary glycoprotein hormone α subunit (αGSU), and luteinizing hormone β subunit (LHβ). A series of deletion mutants of the porcine αGSU (up to −1059 bp) and LHβ (up to −1277 bp) promoters were constructed in the reporter vector, fused with the secreted alkaline phosphatase gene (pSEAP2-Basic). Transient transfection studies using GH3 cells were carried out to estimate the activation of the porcine αGSU and LHβ promoters by Prop-1, which was found to activate the αGSU promoter of −1059/+12 bp up to 11.7-fold but not the LHβ promoter. Electrophoretic mobility shift assay and DNase I footprinting analysis revealed that Prop-1 binds to six positions, −1038/−1026, −942/−928, −495/−479, −338/−326, −153/−146, and −131/−124 bp, that comprise the A/T cluster. Oligonucleotides of six Prop-1 binding sites were directly connected to the minimum promoter of αGSU, fused in the pSEAP2-Basic vector, followed by transfecting GH3 cells to determine the cis-acting activity. Finally, we concluded that at least five Prop-1 binding sites are the cis-acting elements for αGSU gene expression. The present results revealed a notable feature of the proximal region, where three Prop-1-binding sites are close to and/or overlap the pituitary glycoprotein hormone basal element, GATA-binding element, and junctional regulatory element. To our knowledge, this is the first demonstration of the role of Prop-1 in the regulation of αGSU gene expression. These results, taken together with our previous finding that Prop-1 is a transcription factor for FSHβ gene, confirm that Prop-1 modulates the synthesis of FSH at the transcriptional level. On the other hand, the defects of Prop-1 are known to cause dwarfism and combined pituitary hormone deficiency accompanying hypogonadism. Accordingly, the present observations provide a novel view to understand the hypogonadism caused by Prop-1 defects at the molecular level through the regulatory mechanism of αGSU and FSHβ gene expressions.

Download Full-text

Foxa3 (HNF-3γ) binds to and activates the rat proglucagon gene promoter but is not essential for proglucagon gene expression

Biochemical Journal ◽

10.1042/bj20020095 ◽

2002 ◽

Vol 366 (2) ◽

pp. 633-641 ◽

Cited By ~ 23

Author(s):

Yuanfang LIU ◽

Wei SHEN ◽

Patricia L. BRUBAKER ◽

Klaus H. KAESTNER ◽

Daniel J. DRUCKER

Keyword(s):

Gene Expression ◽

Cell Lines ◽

Promoter Activity ◽

Gene Promoter ◽

Forkhead Box ◽

Mild Hypoglycaemia ◽

Element Binding Protein ◽

Prolonged Fast

Members of the Forkhead box a (Foxa) transcription factor family are expressed in the liver, pancreatic islets and intestine and both Foxa1 and Foxa2 regulate proglucagon gene transcription. As Foxa proteins exhibit overlapping DNA-binding specificities, we examined the role of Foxa3 [hepatocyte nuclear factor (HNF)-3γ] in control of proglucagon gene expression. Foxa3 was detected by reverse transcriptase PCR in glucagon-producing cell lines and binds to the rat proglucagon gene G2 promoter element in GLUTag enteroendocrine cells. Although Foxa3 increased rat proglucagon promoter activity in BHK fibroblasts, augmentation of Foxa3 expression did not increase proglucagon promoter activity in GLUTag cells. Furthermore, adenoviral Foxa3 expression did not affect endogenous proglucagon gene expression in islet or intestinal endocrine cell lines. Although Foxa3-/- mice exhibit mild hypoglycaemia during a prolonged fast, the levels of proglucagon-derived peptides and proglucagon mRNA transcripts were comparable in tissues from wild-type and Foxa3-/- mice. These findings identify Foxa3 as a member of the proglucagon gene G2 element binding-protein family that, unlike Foxa1, is not essential for control of islet or intestinal proglucagon gene expression in vivo.

Download Full-text