scholarly journals Identification of FOXO targets that generate diverse features of the diapause phenotype in the mosquito Culex pipiens

2015 ◽  
Vol 112 (12) ◽  
pp. 3811-3816 ◽  
Author(s):  
Cheolho Sim ◽  
David S. Kang ◽  
Sungshil Kim ◽  
Xiaodong Bai ◽  
David L. Denlinger
Keyword(s):  
Binding Site ◽  
Culex Pipiens ◽  
Growth Regulation ◽  
Hormone Signaling ◽  
Forkhead Transcription Factor ◽  
Chip Sequencing ◽  
Physiological Pathways ◽  
Functional Relevance ◽  
Predicted Binding Site ◽  
Do So

Insulin and juvenile hormone signaling direct entry of the mosquito Culex pipiens into its overwintering adult diapause, and these two critical signaling pathways appear to do so by converging on the regulation of forkhead transcription factor (FOXO). Diapause is a complex phenotype, and FOXO emerges as a prime candidate for activating many of the diverse physiological pathways that generate the diapause phenotype. Here, we used ChIP sequencing to identify direct targets of FOXO. The nearest gene in a 10-kb region surrounding a predicted binding site was extracted for each binding site, resulting in a dataset containing genes potentially regulated by FOXO. By selecting candidate genes based on their functional relevance to diapause, we identified five gene categories of potential interest, including stress tolerance, metabolic pathways, lifespan extension, cell cycle and growth regulation, and circadian rhythms. Twelve targets were prioritized for further analysis, 10 of which were validated by ChIP-quantitative PCR and quantitative real-time PCR. These 10 genes activated by FOXO are highly up-regulated during diapause and are thus strong candidates for implementation of the diapause syndrome.

scholarly journals REACTIVE LYSIS: THE COMPLEMENT-MEDIATED LYSIS OF UNSENSITIZED CELLS

1970 ◽  
Vol 131 (4) ◽  
pp. 643-657 ◽  
Author(s):  
P. J. Lachmann ◽  
R. A. Thompson
Keyword(s):  
Binding Site ◽  
Complement Activation ◽  
Stable Complex ◽  
Red Cell ◽  
Complement Components ◽  
Heat Stable ◽  
Human Sera ◽  
Red Cell Membranes ◽  
Short Time ◽  
Do So

It has been shown that the "activated reactor" that is produced in certain human sera by complement activation is a stable complex of the fifth and sixth component of complement (C56). On interaction with C7, the indicator factor, a complex C567 is formed which for a short time (half-life less than 1 min) has an activated binding site and can attach itself to normal red cell membranes, conferring on them the hemolytic properties of the "heat stable" complement intermediate EC 1 ∼ 7, the capacity to be lysed by C8 and C9. These cells have neither antibody nor the complement components up to C3 bound on them. The binding site—activated C567c—can similarly bind to other hydrophobic surfaces, including agarose gel where it forms a "stainable line". If the complex is not bound to a surface, the binding site decays and the resulting complex will no longer give rise to lysis. However it will still inactivate C8 and C9 in solution. The sera that can generate activated reactor apparently do so because they have an excess of C5 and C6, compared to their content of C7. The phenomenon of reactive lysis thus represents complement-mediated lysis of unsensitized cells initiated at the C5 stage by a stable complex (C56) which was generated by complement activation at a distance. The immunochemistry of the phenomenon is described and some of its implications discussed.

Islamic Governance: Strategies for Relevance

2016 ◽  
Vol 2 ◽  
Author(s):  
Mei Chee Yung
Keyword(s):  
International Community ◽  
The Public ◽  
The Core ◽  
Brunei Darussalam ◽  
Agents Of Change ◽  
Governance Strategies ◽  
The Government ◽  
Functional Relevance ◽  
Common Understanding ◽  
Do So

Even though Islam is the official religion of Brunei Darussalam, more efforts are still needed to bolster functionality and relevance of Islam to the country, and implement an Islamic system of governance. This paper sets out to devise strategies in order to do so, to be implemented by three main stakeholders: Government civil service, the public and the international community. Five specific strategies are devised: formulate a single common understanding of Islamic governance; ensure commitment from top management; train and develop competence; engage the public; and engage the international community. The first three strategies relate to the Government, the fourth to the public, and the fifth to the international community. And at the core, of course, is Tauḥīd, or strong Faith, which would act as a guide to help individuals, the main agents of change, make appropriate decisions in accordance to the teachings of Islam, implement the five strategies to strengthen functional relevance of Islam in Brunei, and be able to work towards achieving the Maqāṣid of the Sharī’ah.

scholarly journals MiR-2 family regulates insect metamorphosis by controlling the juvenile hormone signaling pathway

2015 ◽  
Vol 112 (12) ◽  
pp. 3740-3745 ◽  
Author(s):  
Jesus Lozano ◽  
Raúl Montañez ◽  
Xavier Belles
Keyword(s):  
Transcription Factor ◽  
Juvenile Hormone ◽  
Binding Site ◽  
Signaling Pathway ◽  
Blattella Germanica ◽  
Mrna Levels ◽  
Hormone Signaling ◽  
Nymphal Instar ◽  
Insect Metamorphosis ◽  
Krüppel Homolog 1

In 2009 we reported that depletion of Dicer-1, the enzyme that catalyzes the final step of miRNA biosynthesis, prevents metamorphosis inBlattella germanica. However, the precise regulatory roles of miRNAs in the process have remained elusive. In the present work, we have observed that Dicer-1 depletion results in an increase of mRNA levels of Krüppel homolog 1 (Kr-h1), a juvenile hormone-dependent transcription factor that represses metamorphosis, and that depletion of Kr-h1 expression in Dicer-1 knockdown individuals rescues metamorphosis. We have also found that the 3′UTR of Kr-h1 mRNA contains a functional binding site for miR-2 family miRNAs (for miR-2, miR-13a, and miR-13b). These data suggest that metamorphosis impairment caused by Dicer-1 and miRNA depletion is due to a deregulation of Kr-h1 expression and that this deregulation is derived from a deficiency of miR-2 miRNAs. We corroborated this by treating the last nymphal instar ofB. germanicawith an miR-2 inhibitor, which impaired metamorphosis, and by treating Dicer-1-depleted individuals with an miR-2 mimic to allow nymphal-to-adult metamorphosis to proceed. Taken together, the data indicate that miR-2 miRNAs scavenge Kr-h1 transcripts when the transition from nymph to adult should be taking place, thus crucially contributing to the correct culmination of metamorphosis.

scholarly journals The Predicted Binding Site and Dynamics of Peptide Inhibitors to the Methuselah GPCR fromDrosophila melanogaster†

Biochemistry ◽  
2008 ◽  
Vol 47 (48) ◽  
pp. 12740-12749 ◽  
Author(s):  
Jiyoung Heo ◽  
William W. Ja ◽  
Seymour Benzer ◽  
William A. Goddard
Keyword(s):  
Binding Site ◽  
Peptide Inhibitors ◽  
Predicted Binding Site

Cement gland-specific activation of the Xag1 promoter is regulated by co-operation of putative Ets and ATF/CREB transcription factors

Development ◽  
2002 ◽  
Vol 129 (19) ◽  
pp. 4387-4397
Author(s):  
Fiona C. Wardle ◽  
Daniel H. Wainstock ◽  
Hazel L. Sive
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Binding Site ◽  
Reporter Gene ◽  
Binding Sites ◽  
Cement Gland ◽  
Specific Expression ◽  
Necessary And Sufficient ◽  
Do So

The cement gland marks the extreme anterior ectoderm of the Xenopus embryo, and is determined through the overlap of several positional domains. In order to understand how these positional cues activate cement gland differentiation, the promoter of Xag1, a marker of cement gland differentiation, was analyzed. Previous studies have shown that Xag1 expression can be activated by the anterior-specific transcription factor Otx2, but that this activation is indirect. 102 bp of upstream genomic Xag1 sequence restricts reporter gene expression specifically to the cement gland. Within this region, putative binding sites for Ets and ATF/CREB transcription factors are both necessary and sufficient to drive cement gland-specific expression, and cooperate to do so. Furthermore, while the putative ATF/CREB factor is activated by Otx2, a factor acting through the putative Ets-binding site is not. These results suggest that Ets-like and ATF/CREB-like family members play a role in regulating Xag1 expression in the cement gland, through integration of Otx2 dependent and independent pathways.

scholarly journals Inhibition of the Collapse of the Shaker K+ Conductance by Specific Scorpion Toxins

2004 ◽  
Vol 123 (3) ◽  
pp. 265-279 ◽  
Author(s):  
Froylan Gómez-Lagunas ◽  
Cesar V.F. Batista ◽  
Timoteo Olamendi-Portugal ◽  
Martha E. Ramírez-Domínguez ◽  
Lourival D. Possani
Keyword(s):  
Binding Site ◽  
Selectivity Filter ◽  
Channel Block ◽  
Scorpion Toxins ◽  
K Channels ◽  
Outer Vestibule ◽  
Plausible Model ◽  
K Current ◽  
Do So ◽  
External K

The Shaker B K+ conductance (GK) collapses when the channels are closed (deactivated) in Na+ solutions that lack K+ ions. Also, it is known that external TEA (TEAo) impedes the collapse of GK (Gómez-Lagunas, F. 1997. J. Physiol. 499:3–15; Gómez-Lagunas, F. 2001. J. Gen. Physiol. 118:639–648), and that channel block by TEAo and scorpion toxins are two mutually exclusive events (Goldstein, S.A.N., and C. Miller. 1993. Biophys. J. 65:1613–1619). Therefore, we tested the ability of scorpion toxins to inhibit the collapse of GK in 0 K+. We have found that these toxins are not uniform regarding the capacity to protect GK. Those toxins, whose binding to the channels is destabilized by external K+, are also effective inhibitors of the collapse of GK. In addition to K+, other externally added cations also destabilize toxin block, with an effectiveness that does not match the selectivity sequence of K+ channels. The inhibition of the drop of GK follows a saturation relationship with [toxin], which is fitted well by the Michaelis-Menten equation, with an apparent Kd bigger than that of block of the K+ current. However, another plausible model is also presented and compared with the Michaelis-Menten model. The observations suggest that those toxins that protect GK in 0 K+ do so by interacting either with the most external K+ binding site of the selectivity filter (suggesting that the K+ occupancy of only that site of the pore may be enough to preserve GK) or with sites capable of binding K+ located in the outer vestibule of the pore, above the selectivity filter.

scholarly journals Systematic analysis of low-affinity transcription factor binding site clusters in vitro and in vivo establishes their functional relevance

2021 ◽  
Author(s):  
Amir Shahein ◽  
Maria L&oacutepez-Malo ◽  
Ivan Istomin ◽  
Evan J. Olson ◽  
Shiyu Cheng ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Binding Site ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Transcription Factor Binding ◽  
Affinity Binding ◽  
Factor Binding ◽  
Functional Relevance

Transcription factor binding to a single binding site and its functional consequence in a promoter context are beginning to be relatively well understood. However, binding to clusters of sites has yet to be characterized in depth, and the functional relevance of binding site clusters remains uncertain.We employed a high-throughput biochemical method to characterize transcription factor binding to clusters varying across a range of affinities and configurations. We found that transcription factors can bind concurrently to overlapping sites, challenging the notion of binding exclusivity. Further-more, compared to an individual high-affinity binding site, small clusters with binding sites an order of magnitude lower in affinity give rise to higher mean occupancies at physiologically-relevant transcription factor concentrations in vitro. To assess whether the observed in vitro occupancies translate to transcriptional activation in vivo, we tested low-affinity binding site clusters by inserting them into a synthetic minimal CYC1 and the native PHO5 S. cerevisiae promoter. In the minCYC1 promoter, clusters of low-affinity binding sites can generate transcriptional output comparable to a promoter containing three consensus binding sites. In the PHO5 promoter, replacing the native Pho4 binding sites with clusters of low-affinity binding sites recovered activation of these promoters as well. This systematic characterization demonstrates that clusters of low-affinity binding sites achieve substantial occupancies, and that this occupancy can drive expression in eukaryotic promoters

Sign in / Sign up

Export Citation Format

Share Document