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Results for “Response regulator”

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At least 19 recordsLinked to original sources
PubMed2024

PSEUDO-RESPONSE REGULATOR 3b and transcription factor ABF3 modulate abscisic acid-dependent drought stress response in soybean.

The circadian system plays a pivotal role in facilitating the ability of crop plants to respond and adapt to fluctuations in their immediate environment effectively. Despite the increasing comprehension of PSEUDO-RESPONSE REGULATORs and their involvement in the regulation of diverse biological processes, including circadian rhythms, photoperiodic control of flowering, and responses to abiotic stress, the transcriptional networks associated with these factors in soybean (Glycine max (L.) Merr.) remain incompletely characterized. In this study, we provide empirical evidence highlighting the significance of GmPRR3b as a crucial mediator in regulating the circadian clock, drought stress response, and abscisic acid (ABA) signaling pathway in soybeans. A comprehensive analysis of DNA affinity purification sequencing and transcriptome data identified 795 putative target genes directly regulated by GmPRR3b. Among them, a total of 570 exhibited a significant correlation with the response to drought, and eight genes were involved in both the biosynthesis and signaling pathways of ABA. Notably, GmPRR3b played a pivotal role in the negative regulation of the drought response in soybeans by suppressing the expression of abscisic acid-responsive element-binding factor 3 (GmABF3). Additionally, the overexpression of GmABF3 exhibited an increased ability to tolerate drought conditions, and it also restored the hypersensitive phenotype of the GmPRR3b overexpressor. Consistently, studies on the manipulation of GmPRR3b gene expression and genome editing in plants revealed contrasting reactions to drought stress. The findings of our study collectively provide compelling evidence that emphasizes the significant contribution of the GmPRR3b-GmABF3 module in enhancing drought tolerance in soybean plants. Moreover, the transcriptional network of GmPRR3b provides valuable insights into the intricate interactions between this gene and the fundamental biological processes associated with plant adaptation to diverse environmental conditions.

Glycine max↗
PubMed1977

A response regulator model in a simple sensory system.

Bacterial behavior is shown to be modulated through a simple on-off switching device which directs migration toward favorable conditions and away from unfavorable ones. The behavioral response is controlled by a rudimentary memory which allows the bacteria to sense gradients over time. The memory can be explained by a biochemical system involving a response regulator whose level relative to a threshold controls flagellar function. The level of the response regulator is itself controlled by factors such as enzyme levels and environmental stimuli. The molecular basis of the model appears to be relevant to more complex hormonal and neural signaling systems.

Adaptation, Physiological↗
PubMed1975

Steric hindrance of CON A receptor sites by antigen: a possible explanation of Ir regulated responses.

Spleen cells from mice that respond poorly (C57BL/6) or well (CBA, C3H/HeJ AND B6D2F1) to DNP-BGG, an antigen under Ir gene regulation, were cultured with the T cell mitogen Con A and varying concentrations of DNP-BGG and DNP-KLH. It was found that DNP-BGG dpressed the responses of C57BL/6 spleen cells to Con A stimulation to a much greater degree than did DNP-KLH; the Con A stimulated responses of spleen cells from the other strains were impaired equally and less severely by both antigens. The possible implications of these findings with regard to Ir gene regulation of thymus-dependent immune responses were discussed.

Animals↗
PubMed2026

Structural and functional characterization of peanut expansin proteins identifies AhEXPA3 as a stress-responsive regulator of seed germination.

Expansins are cell wall-associated proteins that play important roles in plant growth, development, and environmental responses, yet their structural features and functional significance in peanut remain insufficiently understood. Here, we performed a genome-wide identification and characterization of 70 expansin proteins in cultivated peanut. Phylogenetic analysis classified these genes into four subfamilies (EXPA, EXPB, EXLA, and EXLB), with conserved motif patterns and subgroup-specific exon-intron structures. Collinearity and evolutionary analyses revealed that segmental duplication mainly drove peanut expansin family expansion, with most duplicated gene pairs subsequently undergoing purifying selection. Promoter analysis identified abundant cis-regulatory elements associated with light responses, hormone signaling, and stress responses. Expression profiling indicated that many AhEXP genes were differentially expressed during seed germination and in response to abscisic acid (ABA), salt, and osmotic stresses. Among them, AhEXPA3 was identified as a stress-responsive expansin protein with marked transcriptional induction under abiotic stress conditions. Subcellular localization analysis suggested that AhEXPA3 exhibits an endoplasmic reticulum-associated localization pattern. Functional assays further demonstrated that heterologous expression of AhEXPA3 inhibited seed germination and early seedling establishment under stress conditions in both Arabidopsis thaliana and rice. These findings support a negative regulatory role of AhEXPA3 in stress-responsive seed germination and broaden current understanding of expansin protein function in legumes.

Germination↗
PubMed2026

Allelic variation and light-responsive regulation of FaMYB10-2 underlie tissue-specific anthocyanin accumulation in strawberry.

Anthocyanins critically determine fruit color, nutrition, and stress resilience in cultivated strawberry (Fragaria × ananassa), directly influencing consumer preference. Despite complex genetic and environmental regulation of their biosynthesis, the basis for tissue-specific pigmentation, notably the widespread occurrence of red skin and pale flesh, remains poorly understood. We integrated genomic, transcriptomic, and functional analyses across 200 cultivars to dissect receptacle pigmentation regulation. Approaches included FaMYB10-2 allele mining, promoter structural variant (SV) identification, expression profiling, regulatory interaction assays, and characterization of upstream light-responsive factors. FaMYB10-2 was identified as the key R2R3-MYB regulator of fruit anthocyanin biosynthesis. Alleles FaMYB10-2.2 and FaMYB10-2.3 encode truncated proteins retaining bHLH-binding capacity but lacking activation domains, functioning as dominant-negative repressors. A promoter SV 986 bp upstream of FaMYB10-2 was associated with reduced pale fruit due to cis-regulatory divergence. The SV (Alt) allele is prevalent in Asian cultivars, while the Ref allele is enriched in Western germplasm. Crucially, a light-responsive FaHYH-FaWRKY71 cascade activates FaMYB10-2 and structural genes haplotype-dependently, compensating for weak MYB activity in the skin. Our findings reveal a multilayered regulatory system integrating allelic variation, cis-regulatory divergence, and environmental signals, advancing anthocyanin understanding and providing engineering targets for polyploid crop color improvement.

Fragaria↗
PubMed1979

Suppressor cells for in vivo cytotoxic responses--regulation of the in vivo activation of cytotoxic T-lymphocytes by suppressive cells.

A significant in vivo activation of cytotoxic T-lymphocytes (CTL) against trinitrophenyl (TNP)-modified autologous cells and of a DNA-synthesis response in the peripheral lymphnodes is observed in cyclophosphamide (CyP) treated mice after skinpainting with trinitrochlorbenzene (TNCB) or after injection of TNP-coupled spleen cells (TNP-Spl) into the footpads. The activation of these responses can be suppressed by the transfer of spleen cells or lymphnode cells from skinpainted normal mice, but not from skinpainted mice that had been pretreated with CyP. Suppressive activity is also induced by injections of TNP-Spl i.p. or trinitrobenzosulfonate (TNBS) i.v. Optimal activation of suppression occurs with 3--4 days. The suppressive activity is antigen-specific at least in respect to its activation. Suppressor cells of this kind also suppress the induction of delayed hypersensitivity (DH) responses and the priming for in vitro secondary responses. However, these two responses are less sensitive to the suppression, and their in vivo activation is accordingly much less restricted with the in vivo activation of DNA-synthesis and primary CTL responses. DH and CMC memory can be activated ty TNCB skinpainting without pretreatment with CyP.

Animals↗
PubMed2026

Positional grammar of transcription factor binding partitions developmental and stress-response regulation in plants.

Understanding how transcription factor binding site (TFBS) position influences gene regulation remains a fundamental challenge in plants. Here, we integrate conserved multiDAP TFBS maps for 244 transcription factors (TFs) with single-nucleus chromatin accessibility, cell type-resolved gene expression, and hormone-response datasets across Brassicaceae species to determine how TFBS position relates to regulatory function. Although conserved TFBSs are enriched near transcription start sites (TSSs), TSS-proximal accessibility poorly predicts cell type-specific expression. Instead, cell type-specific expression correlates best with conserved TFBSs embedded in cell type-restricted chromatin, with TF family-specific distributions across distal promoters and introns. In contrast, TSS-proximal TFBSs in broadly accessible chromatin are associated with rapid transcriptional responses to abiotic and biotic stress hormones. Coding sequence TFBSs mark a distinct regulatory context in which the same DNA sequence encodes both amino acid sequence and TF motifs, including evidence that CDS-localized ABR1 binding may contribute to repression during hormone response. Finally, distal upstream regions contain conserved multi-family TF clusters with enhancer-like features overlapping rare cell type-specific accessible chromatin and enriched near genes controlling embryonic, meristematic, and hormone-dependent developmental patterning. Together, these results support a positional grammar in which TFBS position and chromatin context jointly partition developmental, stress-responsive, and repressive regulatory output in plants.

Transcription Factors↗
PubMed2026

Binding analysis of the response regulator NarL protein to the promoter of the O6-methylguanine-DNA methyltransferase (ogt) gene in Salmonella Typhimurium.

BACKGROUND: Salmonella Typhimurium (STM) is a gram-negative bacterium that causes severe gastrointestinal disorders in both animals and humans. The regulation of DNA repair genes is critical for maintaining genomic stability of the bacteria. O6-methylguanine DNA methyltransferase (Ogt), plays a vital role in repairing alkylated DNA in STM; however, the transcriptional regulation of ogt gene remains poorly characterized. Furthermore, NarL is a transcriptional regulator, involved in the pathogenesis of STM under anaerobic condition. Therefore, this study investigated the interaction between NarL protein and the promoter region of the ogt gene. METHODS: In this study, narl gene was cloned in pET32a vector and NarL protein was expressed in Escherichia coli BL21 (DE3). Subsequently, the ogt gene promoter (pogt) was selected, amplified, cloned and its activity was evaluated. Electrophoretic mobility shift assay (EMSA), isothermal titration calorimetry (ITC), molecular docking were employed to elucidate the interaction between NarL protein and ogt promoter. Furthermore, the regulatory role of NarL in ogt gene expression was validated in vivo using RT-qPCR and β-galactosidase assay. RESULTS: This study resulted that NarL protein interacts specifically with the ogt promoter, as confirmed by EMSA and ITC, with ΔG of - 9.42 kcal mol⁻¹. Furthermore, RT-qPCR and β-galactosidase assays demonstrated that deletion of narl significantly (P ≤ 0.01) decreased ogt transcript levels and promoter activity than wild Salmonella Typhimurium, whereas exogenous supplementation of recombinant NarL protein restored the expression. These findings suggest that NarL plays a potential regulatory role in ogt gene expression in response to environmental signals. CONCLUSION: These findings highlight an interaction between NarL protein and the promoter region of ogt gene in Salmonella Typhimurium, linking nitrogen metabolism with the DNA repair pathway in STM, which may contribute to the bacterial survival under nitrosative stress.

Salmonella typhimurium↗
PubMed1979

Hormonal regulation of peptide receptors and target cell responses.

Regulation of plasma membrane receptors for peptide hormones by the prevailing ligand concentration often causes altered target cell function. Receptor number is determined by hormone-induced changes in membrane conformation, irreversible ligand binding, and processing of ligand-receptor complexes during hormone action.

Adenylyl Cyclases↗
PubMed1975

On the regulation of cyclic AMP level in bacteria. II. In vitro regulation of adenylate cyclase activity. Solubilization and reconstitution of a functional membrane-bound adenylate cyclase system responsive to regulation by glucose.

1. The in vitro regulation of the membrane bound adenylate cyclase of Escherichia coli B/r by a variety of carbohydrates and one mammalian hormone was examined. 2. The membrane bound adenylate cyclase was found responsive to regulation by the various growth substrates and to glucagon. 3. Solubilization of the bacterial membrane preparation by a procedure specific for the solubilization of the phosphotransferase enzyme E1 1 to its E1 1 A and E1 1 B subunits was found to be accompanied by the loss of the adenylate cyclase regulation by glucose. 4. Reconstitution of the membrane was found to result in a recovery of the regulative response of the adenylate cyclase to glucose. 5. A model for the intermediate steps in the interaction between glucose and phosphotransferase E1 1 and the adenylate cyclase is discussed.

Adenylyl Cyclases↗
PubMed2025

Systematic acupuncture explains acupuncture at Baihui (GV20) and Fengchi (GB20) targeting the inflammatory response to regulate migraine.

OBJECTIVE: To take Baihui (GV20) and Fengchi (GB20) targeting inflammatory response to regulate migraine as an example to describe a new method for studying the mechanism of stimulating acupoints. METHODS: The target information of Baihui (GV20) and Fengchi (GB20) was retrieved, and after intersection with migraine, Kyoto Encyclopedia of Genes and Genomes (KEGG), Reactome, and UniProt Keywords were used for functional enrichment. After selecting the main pathway, rats were selected and nitroglycerin was used for modeling, and the behavioral scores, inflammatory factors, heme oxygenase 1 (HMOX1), protein kinase B (AKT1), signal transducer and activator of transcription 3 (STAT3), phosphorylated extracellular signal-regulated kinase 1/2 (P-ERK1/ERK2) and other states of the rats in the acupuncture, twisting, and electroacupuncture groups were compared. RESULTS: A total of 135 Baihui (GV20) targets and 27 Fengchi (GB20) targets were collected. A total of 73 target information were obtained after the intersection of these targets in migraine. These 73 targets have three main pathways: hypoxia-inducible factor 1 (HIF-1) signaling pathway, signaling by interleukins and inflammatory response. The main targets in the pathway were verified and found that interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and HMOX1, AKT1, STAT3, P-ERK1/ERK2 can be regulated by Baihui (GV20) and Fengchi (GB20). CONCLUSION: Baihui (GV20) and Fengchi (GB20) can regulate migraine by regulating inflammatory factors and HMOX1, AKT1, STAT3, P-ERK1/ERK2 and other changes in HIF-1 signaling pathway, Signaling by Interleukins and Inflammatory response pathways. Based on systems biology and network pharmacology, and with the model of "acupoint-target-disease", explore the research methods of systematic acupuncture and moxibustion. We believe this is a usable research direction for exploring the mechanism of acupuncture stimulation.

Acupuncture Points↗
PubMed1976

Determinants of antigenic molecules responsible for genetically controlled regulation of immune responses.

The ability of mice bearing the H-2S haplotype to develop helper responses to the random copolymer of Glu,Ala while they developed suppressor responses to the terpolymer of Glu,Ala,Tyr suggested the crucial role of tyrosine in these peptides. On the basis of various considerations, it was postulated that many of the tyrosine residues in Glu,Ala,Tyr would be localized at the NH2-terminal end of the molecule. To verify this hypothesis, a block terpolymer composed of a short sequence of homopolymer tyrosine covalently bound to the random copolymer of Glu,Ala was synthesized. The present studies, using this block terpolymer, demonstrated that the chemical determinants stimulating helper and suppressor responses are distinct and can be present simultaneously in the same molecule. Thus, addition of COOH-terminal tyrosine residues to the Glu,Ala polypeptide converted this immunogenic molecule to an immunosuppressive molecule in mice bearing the H-2S haplotype. The mechanism by which these short sequences of tyrosine influence H-2-linked immune responses remains to be determined.

Alanine↗
PubMed1979

Regulation, professional responsibility, and market forces in the health care field.

In this paper, the author first deals briefly with the general interrelationship of market forces, government regulation, and professional responsibility. He then reviews the Federal Trace Commission's ongoing program involving competition in the health care field. Finally, he attempts to cover some prevalent concerns and what he believes are some misconceptions in the medical community about the commission's involvement in the health area.

Accreditation↗
PubMed1978

Inversion of a behavioral response in bacterial chemotaxis: explanation at the molecular level.

Certain cheU mutants of Salmonella show inverted chemotactic behavior, being repelled by attractants and attracted by repellents. Such a dramatic change in behavioral pattern would seem at first glance to require drastic and complex alterations in the sensory processing system. In fact, the behavior can be explained by a simple shift in the level of a response regulator and the subtle effects of this shift on flagellar function. Flagella can exist in either a left-handed or a right-handed structure depending on applied torsion. Wild-type cells swim smoothly by counterclockwise rotation of a left-handed helical bundle and tumble when the motors briefly reverse to clockwise rotation (normal random motility). The cheU mutation causes a shift in response regulator level relative to the critical threshold value, resulting in extended clockwise operation so that the flagella are fully converted to the right-handed helical form. These cells therefore swim smoothly by clockwise rotation of a right-handed bundle and tumble when the motor briefly reverses to counterclockwise rotation (inverse random motility). Thus, tumbling is associated with brief reversals and not with a particular sense of rotation. A wild-type cell, with its steady-state response regulator level placing it initially in normal random motility, will swim smoothly on addition of attractant, whereas a cheU mutant with inverse random motility will tumble given the same stimulus. The phenomenon illustrates the profound behavioral consequences that can result from a single mutation in a key gene.

Chemotaxis↗