scholarly journals Follicle-Stimulating Hormone (FSH) Transiently Blocks FSH Receptor Transcription by Increasing Inhibitor of Deoxyribonucleic Acid Binding/Differentiation-2 and Decreasing Upstream Stimulatory Factor Expression in Rat Sertoli Cells

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3783-3791 ◽  
Author(s):  
Pushpa Viswanathan ◽  
Michelle A. Wood ◽  
William H. Walker
Keyword(s):  
Protein Binding ◽  
Sertoli Cells ◽  
Fsh Receptor ◽  
Upstream Stimulatory Factor ◽  
Binding Studies ◽  
Nuclear Extracts ◽  
E Box ◽  
Stimulatory Factor ◽  
Stimulation Of

FSH acts through the FSH receptor (FSHR) to modulate cell processes that are required to support developing spermatozoa. Within the testis, only Sertoli cells possess receptors for FSH and are the major targets for this regulator of spermatogenesis. FSH stimulation of Sertoli cells for 24–48 h is known to induce Fshr mRNA expression through an E-box motif (CACGTG) located 25 bp upstream of the transcription start site. In contrast, FSH stimulation for 8 h inhibits Fshr transcription. DNA-protein binding studies performed using nuclear extracts from Sertoli cells show that protein binding to the Fshr promoter E-box was reduced 68% after 6 h of FSH stimulation but increased 191% over basal levels after 48 h of stimulation. The proteins binding to the Fshr E-box were identified as upstream stimulatory factor (USF)-1 and -2. FSH stimulation transiently decreased USF1 levels and increased the expression of the inhibitor of DNA binding/differentiation (ID)-2 repressor protein with the same kinetics as the decreased USF/E-box interactions. Overexpression of ID2 resulted in a dose-dependent decrease in USF-driven Fshr promoter activity in the MSC-1 Sertoli cell line, and ID2 inhibited USF binding to the Fshr E-box. Together, these studies suggest that stimulation of Sertoli cells with FSH transiently decreases expression of the USF1 activator and induces accumulation of the ID2 repressor, to block USF binding to the Fshr promoter and delay activation of Fshr transcription. This FSH-regulated mechanism may explain the cyclical changes in Fshr expression that occurs in Sertoli cells in vivo.

scholarly journals In Vivo Regulation of Follicle-Stimulating Hormone Receptor by the Transcription Factors Upstream Stimulatory Factor 1 and Upstream Stimulatory Factor 2 Is Cell Specific

Endocrinology ◽  
2008 ◽  
Vol 149 (10) ◽  
pp. 5297-5306 ◽  
Author(s):  
Brian P. Hermann ◽  
Kaori Hornbaker ◽  
Daren A. Rice ◽  
Michele Sawadogo ◽  
Leslie L. Heckert
Keyword(s):  
Granulosa Cells ◽  
Sertoli Cells ◽  
Chromatin Immunoprecipitation ◽  
Leucine Zipper ◽  
Specific Binding ◽  
Pubertal Timing ◽  
Upstream Stimulatory Factor ◽  
Stimulatory Factor

Pituitary FSH promotes pubertal timing and normal gametogenesis by binding its receptor (FSHR) located on Sertoli and granulosa cells of the testis and ovary, respectively. Studies on Fshr transcription provide substantial evidence that upstream stimulatory factor (USF) 1 and USF2, basic helix-loop-helix leucine zipper proteins, regulate Fshr through an E-box within its promoter. However, despite the strong in vitro support for USF1 and USF2 in Fshr regulation, there is currently no in vivo corroborating evidence. In the present study, chromatin immunoprecipitation demonstrated specific binding of USF1 and USF2 to the Fshr promoter in both Sertoli and granulosa cells, in vivo. Control cells lacking Fshr expression showed no USF-Fshr promoter binding, thus correlating USF-promoter binding to gene activity. Evaluation of Fshr expression in Usf1 and Usf2 null mice further explored USF’s role in Fshr transcription. Loss of either gene significantly reduced ovarian Fshr levels, whereas testis levels were unaltered. Chromatin immunoprecipitation analysis of USF-Fshr promoter binding in Usf-null mice indicated differences in the composition of promoter-bound USF dimers in granulosa and Sertoli cells. Promoter-bound USF dimer levels declined in granulosa cells from both null mice, despite increased USF2 levels in Usf1-null ovaries. However, compensatory increases in promoter-bound USF homodimers were evident in Usf-null Sertoli cells. In summary, this study provides the first in vivo evidence that USF1 and USF2 bind the Fshr promoter and revealed differences between Sertoli and granulosa cells in compensatory responses to USF loss and the USF dimeric composition required for Fshr transcription.

scholarly journals Mutational and in vitro protein-binding studies on centromere DNA from Saccharomyces cerevisiae.

1987 ◽  
Vol 7 (12) ◽  
pp. 4522-4534 ◽  
Author(s):  
R Ng ◽  
J Carbon
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Binding ◽  
In Vitro Assays ◽  
Binding Studies ◽  
Mobility Shift ◽  
Sequence Element ◽  
Sequence Elements ◽  
Mobility Shift Assay

Centromeres on chromosomes in the yeast Saccharomyces cerevisiae contain approximately 140 base pairs (bp) of DNA. The functional centromere (CEN) region contains three important sequence elements (I, PuTCACPuTG; II, 78 to 86 bp of high-AT DNA; and III, a conserved 25-bp sequence with internal bilateral symmetry). Various point mutations or deletions in the element III region have a profound effect on CEN function in vivo, indicating that this DNA region is a key protein-binding site. This has been confirmed by the use of two in vitro assays to detect binding of yeast proteins to DNA fragments containing wild-type or mutationally altered CEN3 sequences. An exonuclease III protection assay was used to demonstrate specific binding of proteins to the element III region of CEN3. In addition, a gel DNA fragment mobility shift assay was used to characterize the binding reaction parameters. Sequence element III mutations that inactivate CEN function in vivo also prevent binding of proteins in the in vitro assays. The mobility shift assay indicates that double-stranded DNAs containing sequence element III efficiently bind proteins in the absence of sequence elements I and II, although the latter sequences are essential for optimal CEN function in vivo.

scholarly journals Forkhead Box A1 (FOXA1) and A2 (FOXA2) Oppositely Regulate Human Type 1 Iodothyronine Deiodinase Gene in Liver

Endocrinology ◽  
2012 ◽  
Vol 153 (1) ◽  
pp. 492-500 ◽  
Author(s):  
Naotetsu Kanamoto ◽  
Tetsuya Tagami ◽  
Yoriko Ueda-Sakane ◽  
Masakatsu Sone ◽  
Masako Miura ◽  
...  
Keyword(s):  
Binding Site ◽  
Promoter Activity ◽  
Short Interfering Rna ◽  
Upstream Stimulatory Factor ◽  
Iodothyronine Deiodinase ◽  
Forkhead Box ◽  
E Box ◽  
Stimulatory Factor ◽  
Interfering Rna

Type 1 iodothyronine deiodinase (D1), a selenoenzyme that catalyzes the bioactivation of thyroid hormone, is expressed mainly in the liver. Its expression and activity are modulated by several factors, but the precise mechanism of its transcriptional regulation remains unclear. In the present study, we have analyzed the promoter of human D1 gene (hDIO1) to identify factors that prevalently increase D1 activity in the human liver. Deletion and mutation analyses demonstrated that a forkhead box (FOX)A binding site and an E-box site within the region between nucleotides −187 and −132 are important for hDIO1 promoter activity in the liver. EMSA demonstrated that FOXA1 and FOXA2 specifically bind to the FOXA binding site and that upstream stimulatory factor (USF) specifically binds to the E-box element. Overexpression of FOXA2 decreased hDIO1 promoter activity, and short interfering RNA-mediated knockdown of FOXA2 increased the expression of hDIO1 mRNA. In contrast, overexpression of USF1/2 increased hDIO1 promoter activity. Short interfering RNA-mediated knockdown of FOXA1 decreased the expression of hDIO1 mRNA, but knockdown of both FOXA1 and FOXA2 restored it. The response of the hDIO1 promoter to USF was greatly attenuated in the absence of FOXA1. Taken together, these results indicate that a balance of FOXA1 and FOXA2 expression modulates hDIO1 expression in the liver.

Controlling the Physical Behavior and Biological Performance of Liposome Formulations Through Use of Surface Grafted Poly(ethylene Glycol)

2002 ◽  
Vol 22 (2) ◽  
pp. 225-250 ◽  
Author(s):  
C. Allen ◽  
N. Dos Santos ◽  
R. Gallagher ◽  
G.N.C. Chiu ◽  
Y. Shu ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Protein Binding ◽  
Chemical Properties ◽  
Total Serum Protein ◽  
Total Serum ◽  
Poly Ethylene Glycol ◽  
Binding Studies ◽  
Poly Ethylene

The presence of poly(ethylene glycol) (PEG) at the surface of a liposomal carrier has been clearly shown to extend the circulation lifetime of the vehicle. To this point, the extended circulation lifetime that the polymer affords has been attributed to the reduction or prevention of protein adsorption. However, there is little evidence that the presence of PEG at the surface of a vehicle actually reduces total serum protein binding. In this review we examine all aspects of PEG in order to gain a better understanding of how the polymer fulfills its biological role. The physical and chemical properties of the polymer are explored and compared to properties of other hydrophilic polymers. An evidence based assessment of several in vitro protein binding studies as well as in vivo pharmacokinetics studies involving PEG is included. The ability of PEG to prevent the self-aggregation of liposomes is considered as a possible means by which it extends circulation longevity. Also, a “dysopsonization” phenomenon where PEG actually promotes binding of certain proteins that then mask the vehicle is discussed.

scholarly journals Upstream stimulatory factor activates the vasopressin promoter via multiple motifs, including a non-canonical E-box

2003 ◽  
Vol 369 (3) ◽  
pp. 549-561 ◽  
Author(s):  
Judy M. COULSON ◽  
Jodie L. EDGSON ◽  
Zoe V. MARSHALL-JONES ◽  
Robert MULGREW ◽  
John P. QUINN ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Dominant Negative ◽  
Site Directed Mutagenesis ◽  
Upstream Stimulatory Factor ◽  
Mobility Shift ◽  
Transcriptional Initiation ◽  
E Box ◽  
E Boxes ◽  
Stimulatory Factor

We have described previously a complex E-box enhancer (-147) of the vasopressin promoter in small-cell lung cancer (SCLC) extracts [Coulson, Fiskerstrand, Woll and Quinn, (1999) Biochem. J. 344, 961—970]. Upstream stimulatory factor (USF) heterodimers were one of the complexes binding to this site in vitro. We now report that USF overexpression in non-SCLC (NSCLC) cells can functionally activate vasopressin promoter-driven reporters that are otherwise inactive in this type of lung cancer cell. Site-directed mutagenesis and electrophoretic mobility-shift analysis demonstrate that although the −147 E-box contributes, none of the previously predicted E-boxes (-147, −135, −34) wholly account for this USF-mediated activation in NSCLC. 5′ Deletion showed the key promoter region as −52 to +42; however, USF-2 binding was not reliant on the −34 E-box, but on a novel adjacent CACGGG non-canonical E-box at −42 (motif E). This mediated USF binding in both SCLC and USF-2-transfected NSCLC cells. Mutation of motif E or the non-canonical TATA box abolished activity, implying both are required for transcriptional initiation on overexpression of USF-2. Co-transfected dominant negative USF confirmed that binding was required through motif E for function, but that the classical activation domain of USF was not essential. USF-2 bound motif E with 10-fold lower affinity than the −147 E-box. In NSCLC, endogenous USF-2 expression is low, and this basal level appears to be insufficient to activate transcription of arginine vasopressin (AVP). In summary, we have demonstrated a novel mechanism for USF activation, which contributes to differential vasopressin expression in lung cancer.

The thyroid hormone analogue SKF L-94901: nuclear occupancy and serum binding studies

1989 ◽  
Vol 76 (5) ◽  
pp. 495-501 ◽  
Author(s):  
John W. Barlow ◽  
Lorna E. Raggatt ◽  
Chen-Fee Lim ◽  
Sharon L. Munro ◽  
Duncan J. Topliss ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Serum Proteins ◽  
Binding Studies ◽  
Hormone Analogue ◽  
Isolated Nuclei ◽  
Whole Cells ◽  
High Affinity ◽  
Nuclear Extracts

1. We studied a brominated thyroid hormone analogue, SKF L-94901, which has the potential to lower serum cholesterol without adverse cardiovascular effects. This compound is about 50% as active as tri-iodothyronine (T3) in liver nuclear receptor binding in vivo but only 1% as active in vitro and has nearly 200 times more enzyme-inducing activity in liver than in heart. Our aim was to examine the interaction of SKF L-94901 with [125I]T3 binding to the intact nuclei in whole cells, isolated nuclei and nuclear extracts of human HeLa cells and to investigate the binding of this compound to human serum. 2. Relative to thyroxine (T4), the affinity of this compound for T4-binding globulin was 0.0035%, for transthyretin 1.66% and for albumin 1.26%. Low affinity for serum proteins, with a relatively high circulating free fraction, could explain why SKF L-94901 is more potent in vivo than in vitro. 3. Human HeLa cell nuclei, isolated after whole-cell incubations, bound [125I]T3 with high affinity (Kd = 78 ± 8 pmol/l, mean ± sem), which was displaceable by T3 analogues in the order Triac {[4-(4-hydroxy-3-iodophenoxy)-3,5-di-iodophenyl]acetic acid} > T3 > T4 ≫ reverse T3. Similar high-affinity (Kd = 58 ± 6 pmol/l, mean ± sem) and identical specificity was observed in high-salt (0.4 mol/l KCl) nuclear extracts. In nuclei of whole cells incubated with [125I]T3 and SKF L-94901, the analogue was 0.8% as potent as T3, whereas in experiments with nuclear extract, the analogue was 7.7% as potent as T3. Results from incubation of T3 with isolated nuclei were virtually identical to those obtained with nuclear extracts. 4. These results suggest an extranuclear component may be involved in restricting access of SKF L-94901 to the nucleus. Whether such mechanisms account for observed differences in its effects on different tissues with reduced influence of SKF L-94901 on cardiac tissue remains to be established. 5. We conclude that SKF L-94901 is weakly bound in serum and shows less potent competition for T3 nuclear binding after incubation of whole cells than after incubation with nuclear extracts or isolated nuclei. This compound may allow further analysis of intracellular mechanisms of thyroid hormone transport and action.

Transcriptional regulation of the human cystathionine β-synthase −1b basal promoter: synergistic transactivation by transcription factors NF-Y and Sp1/Sp3

2001 ◽  
Vol 357 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Yubin GE ◽  
Mark A. KONRAD ◽  
Larry H. MATHERLY ◽  
Jeffrey W. TAUB
Keyword(s):  
Reporter Gene ◽  
Intermediate Step ◽  
Nuclear Factor ◽  
Upstream Stimulatory Factor ◽  
E Box ◽  
Gc Box ◽  
Specific Regulation ◽  
Specificity Protein ◽  
Upstream Stimulatory Factor 1 ◽  
Stimulatory Factor

Cystathionine β-synthase (CBS) catalyses the condensation of serine and homocysteine to form cystathionine, an intermediate step in the synthesis of cysteine. Human CBS encodes five distinct 5′ non-coding exons, the most frequent termed CBS −1a and CBS −1b, each transcribed from its own unique GC-rich TATA-less promoter. The minimal transcriptional region (−3792 to −3667) of the CBS −1b promoter was defined by 5′- and 3′-deletions, and transient transfections of reporter gene constructs in HepG2 cells, characterized by CBS transcription exclusively from the −1b promoter. Included in this 125bp region are 3 GC-boxes (termed GC-a, GC-b and GC-c), an inverted CAAT-box and an E-box. By gel-shift and supershift assays, binding of specificity protein (Sp)1 and Sp3 to the GC-box elements, upstream stimulatory factor 1 (USF-1) to the E-box, and both nuclear factor (NF)-Y and an NF-1-like factor to the CAAT box could be demonstrated. By transient trans fections and reporter gene assays in HepG2 and Drosophila SL2 cells, a functional interplay was indicated between NF-Y binding to the CAAT-box, or between USF-1 binding to the E-box, and Sp1/Sp3 binding to the GC-box elements. In SL2 cells, NF-Y and Sp1/Sp3 were synergistic. Furthermore, both Sp1 and the long Sp3 isoform transactivated the CBS −1b minimal promoter; however, the short Sp3 isoforms were potent repressors. These results may explain the cell- or tissue-specific regulation of CBS transcription, and clarify the bases for alterations in CBS gene expression in human disease and Down's syndrome.

Sign in / Sign up

Export Citation Format

Share Document