Ceramide decreases surfactant protein B gene expression via downregulation of TTF-1 DNA binding activity

2006 ◽  
Vol 290 (2) ◽  
pp. L351-L358 ◽  
Author(s):  
Loretta Sparkman ◽  
Hemakumar Chandru ◽  
Vijayakumar Boggaram
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Dna Binding ◽  
Promoter Activity ◽  
Surfactant Protein ◽  
Binding Activity ◽  
Mrna Levels ◽  
Dna Binding Activity ◽  
Surfactant Protein B ◽  
Tnf Α

Ceramide, a sphingolipid, is an important signaling molecule in the inflammatory response. Mediators of acute lung injury such as TNF-α, platelet-activating factor, and Fas/Apo ligand stimulate sphingomyelin hydrolysis to increase intracellular ceramide levels. Surfactant protein B (SP-B), a hydrophobic protein of pulmonary surfactant, is essential for surfactant function and lung stability. In this study we investigated the effects of ceramide on SP-B gene expression in H441 lung epithelial cells. Ceramide decreased SP-B mRNA levels in control and dexamethasone-treated cells after 24-h incubation and inhibition of SP-B mRNA was associated with inhibition of immunoreactive SP-B. In transient transfections assays, ceramide inhibited SP-B promoter activity, indicating that the inhibitory effects are exerted at the transcriptional level. Deletion mapping experiments showed that the ceramide-responsive region is located within the −233/−80-bp region of human SP-B promoter. Electrophoretic mobility shift and reporter assays showed that ceramide reduced the DNA binding activity and transactivation capability of thyroid transcription factor 1 (TTF-1/Nkx2.1), a key factor for SP-B promoter activity. Collectively these data showed that ceramide inhibits SP-B gene expression by reducing the DNA biding activity of TTF-1/Nkx2.1 transcription factor. Protein kinase C inhibitor bisindolylmaleimide and the protein tyrosine kinase inhibitor genistein partially reversed ceramide inhibition, indicating that protein kinases play important roles in the ceramide inhibition of SP-B gene expression. Chemical inhibitors of de novo ceramide synthesis and sphingomyelin hydrolysis had no effect on TNF-α inhibition of SP-B promoter activity and mRNA levels, suggesting that ceramide does not play a role in the inhibition.

scholarly journals USF1 and USF2 Mediate Inhibition of Human Trophoblast Differentiation and CYP19 Gene Expression by Mash-2 and Hypoxia

2003 ◽  
Vol 23 (17) ◽  
pp. 6117-6128 ◽  
Author(s):  
Bing Jiang ◽  
Carole R. Mendelson
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Promoter Activity ◽  
Leucine Zipper ◽  
Binding Activity ◽  
The Other ◽  
Mrna Levels ◽  
Human Trophoblast ◽  
Other Hand ◽  
E Boxes

ABSTRACT In the human placental syncytiotrophoblast, C19 steroids are converted to estrogens by aromatase P450, product of the CYP19 gene. When human cytotrophoblasts, which lack the capacity to express aromatase, are cultured in 20% O2, they spontaneously fuse to form a multinuclear syncytiotrophoblast and CYP19 expression is markedly induced. On the other hand, when cytotrophoblasts are cultured in 2% O2, syncytiotrophoblast differentiation and induction of CYP19 expression are prevented. We previously observed that expression of the transcription factor Mash-2 (mammalian achaete/scute homologue 2), which is elevated in human cytotrophoblasts and maintained at elevated levels by hypoxia, declines with syncytiotrophoblast differentiation. Overexpression of Mash-2 prevents syncytiotrophoblast differentiation and induction of CYP19 expression. In the present study, we observed that unexpectedly immunoreactive Mash-2 protein was localized predominately to the cytoplasm of human cytotrophoblasts. Elevated cytoplasmic levels of Mash-2 were maintained when trophoblasts were cultured in 2% O2 and declined to undetectable levels upon culture in 20% O2. Previously, we found that Mash-2 inhibited CYP19 promoter activity through sequences within a 350-bp region upstream and within placenta-specific exon I.1 containing three E boxes (E1 at −325 bp, 5′-CACTTG-3′; E2 at −58 bp, 5′-CACATG-3′; and E3 at +26 bp, 5′-CACGTG-3′). In this study, we found that trophoblast nuclear protein binding to these E boxes declined with syncytiotrophoblast differentiation in 20% O2 and was induced by hypoxia; however, Mash-2 did not appear to bind to any of these E boxes. On the other hand, the basic helix-loop-helix leucine zipper transcription factors upstream stimulatory factors 1 and 2 (USF1 and USF2) did bind to E2 and E3 but not E1. Nuclear levels of USF1 and USF2 and DNA-binding activity declined with syncytiotrophoblast differentiation and were maintained at elevated levels by hypoxia and overexpression of Mash-2, whereas USF1 mRNA levels were unaffected. Finally, USF1 overexpression in cultured human trophoblasts markedly inhibited endogenous CYP19 expression, differentiation of cultured human trophoblast cells, and CYP19 promoter activity. These findings suggest that increased protein levels and DNA binding of USF1 and USF2 mediate the inhibitory effects of hypoxia and of Mash-2 on CYP19 gene expression in human placenta.

scholarly journals Physical interaction of tumour suppressor p53/p73 with CCAAT-binding transcription factor 2 (CTF2) and differential regulation of human high-mobility group 1 (HMG1) gene expression

2003 ◽  
Vol 371 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Hidetaka URAMOTO ◽  
Hiroto IZUMI ◽  
Gunji NAGATANI ◽  
Haruki OHMORI ◽  
Naofumi NAGASUE ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Replication ◽  
Dna Binding ◽  
Promoter Activity ◽  
High Mobility ◽  
Binding Activity ◽  
Physical Interaction ◽  
Dna Binding Activity ◽  
P21 Promoter ◽  
Group 1

The CCAAT-binding transcription factor (CTF)/nuclear factor I (NF-I) group of cellular DNA-binding proteins recognizes the sequence GCCAAT and is implicated in eukaryotic transcription, as well as DNA replication. Molecular analysis of human CTF/NF-I cDNA clones revealed multiple mRNA species that contain alternative coding regions, apparently as a result of differential splicing. Expression and functional analysis established that individual gene products can bind to GCCAAT recognition sites and serve as both promoter-selective transcriptional activators and initiation factors for DNA replication. The interaction between CTF2 and p53/p73 was shown to modulate their ability to regulate transcription of their respective target genes. In the present paper, we report that p53 down-regulates the activity of the high mobility group 1 (HMG1) gene promoter, whereas p73α up-regulates the activity of this promoter. Furthermore, CTF2 transactivates p53-induced p21 promoter activity, but inhibits p73α-induced p21 promoter activity. Using deletion mutants, we found that the DNA-binding domains of both p53 and p73α are required for physical interaction with CTF2 via the regions between amino acid residues 161 and 223, and 228 and 312 respectively. CTF2 enhances the DNA-binding activity of p53 and inhibits the DNA-binding activity of p73α. These results provide novel information on the functional interplay between CTF2 and p53/p73 as important determinants of their function in cell proliferation, apoptosis, DNA repair and cisplatin resistance.

Extinction of insulin gene expression in hybrids between beta cells and fibroblasts is accompanied by loss of the putative beta-cell-specific transcription factor IEF1

1991 ◽  
Vol 11 (3) ◽  
pp. 1547-1552
Author(s):  
D Leshkowitz ◽  
M D Walker
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Binding Activity ◽  
Insulin Gene ◽  
Hybrid Cells ◽  
Dna Binding Activity ◽  
Insulin Producing Cells ◽  
Insulin Gene Expression ◽  
Insulinoma Cells

Insulin-producing cells and fibroblasts were fused to produce hybrid lines. In hybrids derived from both hamster and rat insulinoma cells, no insulin mRNA could be detected in any of seven lines examined by Northern (RNA) analysis despite the presence in each line of the insulin genes of both parental cells. Hybrid cells were transfected with recombinant chloramphenicol acetyltransferase plasmids containing defined segments of the rat insulin I gene 5' flank. We observed no transcriptional activity of the intact insulin enhancer or of IEB2, a critical cis-acting element of the insulin enhancer. IEB2 has previously been shown to interact in vitro with IEF1, a DNA-binding activity observed selectively in insulin-producing cells. Hybrid cells showed no detectable IEF1 activity. Furthermore, the insulin enhancer was unable to reduce transcription directed by the Moloney sarcoma virus enhancer in a double-enhancer construct. Thus, extinction of insulin gene expression in the hybrids apparently does not operate through a direct action of repressors on the insulin enhancer; rather, extinction is accompanied by, and may be caused by, reduced DNA-binding activity of the putative transcriptional activator IEF1.

A single polypeptide possesses the binding and transcription activities of the adenovirus major late transcription factor

1986 ◽  
Vol 6 (12) ◽  
pp. 4723-4733
Author(s):  
L A Chodosh ◽  
R W Carthew ◽  
P A Sharp
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Site ◽  
Rna Polymerase Ii ◽  
Sodium Dodecyl ◽  
Binding Activity ◽  
Affinity Column ◽  
Dna Binding Activity ◽  
Dna Fragment

A simple approach has been developed for the unambiguous identification and purification of sequence-specific DNA-binding proteins solely on the basis of their ability to bind selectively to their target sequences. Four independent methods were used to identify the promoter-specific RNA polymerase II transcription factor MLTF as a 46-kilodalton (kDa) polypeptide. First, a 46-kDa protein was specifically cross-linked by UV irradiation to a body-labeled DNA fragment containing the MLTF binding site. Second, MLTF sedimented through glycerol gradients at a rate corresponding to a protein of native molecular weight 45,000 to 50,000. Third, a 46-kDa protein was specifically retained on a biotin-streptavidin matrix only when the DNA fragment coupled to the matrix contained the MLTF binding site. Finally, proteins from the most highly purified fraction which were eluted and renatured from the 44- to 48-kDa region of a sodium dodecyl sulfate-polyacrylamide gel exhibited both binding and transcription-stimulatory activities. The DNA-binding activity was purified 100,000-fold by chromatography through three conventional columns plus a DNA affinity column. Purified MLTF was characterized with respect to the kinetic and thermodynamic properties of DNA binding. These parameters indicate a high degree of occupancy of MLTF binding sites in vivo.

Cloning and characterization of E2F-2, a novel protein with the biochemical properties of transcription factor E2F

1993 ◽  
Vol 13 (12) ◽  
pp. 7802-7812
Author(s):  
M Ivey-Hoyle ◽  
R Conroy ◽  
H E Huber ◽  
P J Goodhart ◽  
A Oliff ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Hela Cell ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Amino Acid Identity ◽  
Biochemical Properties ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Novel Protein

E2F is a mammalian transcription factor that appears to play an important role in cell cycle regulation. While at least two proteins (E2F-1 and DP-1) with E2F-like activity have been cloned, studies from several laboratories suggest that additional homologs may exist. A novel protein with E2F-like properties, designated E2F-2, was cloned by screening a HeLa cDNA library with a DNA probe derived from the DNA binding domain of E2F-1 (K. Helin, J. A. Lees, M. Vidal, N. Dyson, E. Harlow, and A. Fattaey, Cell 70:337-350, 1992). E2F-2 exhibits overall 46% amino acid identity to E2F-1. Both the sequence and the function of the DNA and retinoblastoma gene product binding domains of E2F-1 are conserved in E2F-2. The DNA binding activity of E2F-2 is dramatically enhanced by complementation with particular sodium dodecyl sulfate-polyacrylamide gel electrophoresis-purified components of HeLa cell E2F, and anti-E2F-2 antibodies cross-react with components of purified HeLa cell E2F. These observations are consistent with a model in which E2F binds DNA as a heterodimer of two distinct proteins, and E2F-2 is functionally and immunologically related to one of these proteins.

NG-monomethyl-l-arginine inhibits erythropoietin gene expression by stimulating GATA-2

Blood ◽  
2000 ◽  
Vol 96 (5) ◽  
pp. 1716-1722 ◽  
Author(s):  
Takahisa Tarumoto ◽  
Shigehiko Imagawa ◽  
Ken Ohmine ◽  
Tadashi Nagai ◽  
Masato Higuchi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Messenger Rna ◽  
Promoter Activity ◽  
Binding Activity ◽  
Guanosine Monophosphate ◽  
Mobility Shift ◽  
Enhancer Activity ◽  
Gata Transcription Factor ◽  
Hep3b Cells

Abstract NG-monomethyl-l-arginine (L-NMMA) has been reported to be elevated in uremic patients. Based on the hypothesis that the pathogenesis of the anemia of renal disease might be due to the perturbation of transcription factors of the erythropoietin (Epo) gene by L-NMMA, the present study was designed to investigate the effect of L-NMMA on Epo gene expression through the GATA transcription factor. L-NMMA caused decreased levels of NO, cyclic guanosine monophosphate (cGMP), and Epo protein in Hep3B cells. L-NAME (analogue of L-NMMA) also inhibited Epo production in anemic mice. Transfection of the Epo promoter-luciferase gene into Hep3B cells revealed that L-NMMA inhibited the Epo promoter activity. However, L-NMMA did not inhibit the Epo promoter activity when mutated Epo promoter (GATA to TATA) was transfected, and L-NMMA did not affect the enhancer activity. Electrophoretic mobility shift assays demonstrated the stimulation of GATA binding activity by L-NMMA. However, L-NMMA had no effect on the binding activity of hepatic nuclear factor-4, COUP-TF1, hypoxia-inducing factor-1, or NF-κB. Furthermore, cGMP inhibited the L-NMMA–induced GATA binding activity. L-NMMA also increased GATA-2 messenger RNA expression. These results demonstrate that L-NMMA suppresses Epo gene expression by up-regulation of the GATA transcription factor and support the hypothesis that L-NMMA is one of the candidate substances that underlie the pathogenesis of renal anemia.

Sign in / Sign up

Export Citation Format

Share Document