scholarly journals A unique HMG-box domain of mouse Maelstrom binds structured RNA but not double stranded DNA

2015 ◽  
Author(s):  
Pavol Genzor ◽  
Alex Bortvin
Keyword(s):  
High Mobility ◽  
Rnase H ◽  
Nucleic Acid Binding ◽  
Specific Domain ◽  
Hmg Box ◽  
Germ Cell Differentiation ◽  
Double Stranded Dna ◽  
Arginine Residues ◽  
And Function

Piwi-interacting piRNAs are a major and essential class of small RNAs in the animal germ cells with a prominent role in transposon control. Efficient piRNA biogenesis and function require a cohort of proteins conserved throughout the animal kingdom. Here we studied Maelstrom (MAEL), which is essential for piRNA biogenesis and germ cell differentiation in flies and mice. MAEL contains a high mobility group (HMG)-box domain and a Maelstrom-specific domain with a presumptive RNase H-fold. We employed a combination of sequence analyses, structural and biochemical approaches to evaluate and compare nucleic acid binding of mouse MAEL HMG-box to that of canonical HMG-box domain proteins (SRY and HMGB1a). MAEL HMG-box failed to bind double-stranded (ds)DNA but bound to structured RNA. We also identified important roles of a novel cluster of arginine residues in MAEL HMG-box in these interactions. Cumulatively, our results suggest that the MAEL HMG-box domain may contribute to MAEL function in selective processing of retrotransposon RNA into piRNAs. In this regard, a cellular role of MAEL HMG-box domain is reminiscent of that of HMGB1 as a sentinel of immunogenic nucleic acids in the innate immune response.

scholarly journals Analysis and Molecular Determinants of HIV RNase H Cleavage Specificity at the PPT/U3 Junction

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 131
Author(s):  
Mar Álvarez ◽  
Enrique Sapena-Ventura ◽  
Joanna Luczkowiak ◽  
Samara Martín-Alonso ◽  
Luis Menéndez-Arias
Keyword(s):  
Dna Synthesis ◽  
Large Subunit ◽  
Rnase H ◽  
Reverse Transcriptases ◽  
Cleavage Specificity ◽  
Double Stranded Dna ◽  
Molecular Determinants ◽  
Rt Inhibitors ◽  
Viral Genomic Rna

HIV reverse transcriptases (RTs) convert viral genomic RNA into double-stranded DNA. During reverse transcription, polypurine tracts (PPTs) resilient to RNase H cleavage are used as primers for plus-strand DNA synthesis. Nonnucleoside RT inhibitors (NNRTIs) can interfere with the initiation of plus-strand DNA synthesis by enhancing PPT removal, while HIV RT connection subdomain mutations N348I and N348I/T369I mitigate this effect by altering RNase H cleavage specificity. Now, we demonstrate that among approved nonnucleoside RT inhibitors (NNRTIs), nevirapine and doravirine show the largest effects. The combination N348I/T369I in HIV-1BH10 RT has a dominant effect on the RNase H cleavage specificity at the PPT/U3 site. Biochemical studies showed that wild-type HIV-1 and HIV-2 RTs were able to process efficiently and accurately all tested HIV PPT sequences. However, the cleavage accuracy at the PPT/U3 junction shown by the HIV-2EHO RT was further improved after substituting the sequence YQEPFKNLKT of HIV-1BH10 RT (positions 342–351) for the equivalent residues of the HIV-2 enzyme (HQGDKILKV). Our results highlight the role of β-sheets 17 and 18 and their connecting loop (residues 342–350) in the connection subdomain of the large subunit, in determining the RNase H cleavage window of HIV RTs.

scholarly journals TOX as a potential target for immunotherapy in lymphocytic malignancies

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Chaofeng Liang ◽  
Shuxin Huang ◽  
Yujie Zhao ◽  
Shaohua Chen ◽  
Yangqiu Li
Keyword(s):  
T Cell ◽  
Potential Role ◽  
Hematological Malignancies ◽  
High Mobility ◽  
High Mobility Group ◽  
Biological Functions ◽  
Hmg Box ◽  
Cell Exhaustion ◽  
Potential Target

AbstractTOX (thymocyte selection-associated HMG BOX) is a member of a family of transcriptional factors that contain the highly conserved high mobility group box (HMG-box) region. Increasing studies have shown that TOX is involved in maintaining tumors and promoting T cell exhaustion. In this review, we summarized the biological functions of TOX and its contribution as related to lymphocytic malignancies. We also discussed the potential role of TOX as an immune biomarker and target in immunotherapy for hematological malignancies.

Effects of P-gpMAbNano-structured material nanoparticles on epilepsy and expression of SRY-related HMG Box 21 in epilepsy

2020 ◽  
Vol 10 (4) ◽  
pp. 585-593
Author(s):  
Qi Li ◽  
Jing Deng ◽  
Juan Yang ◽  
Tao Xu ◽  
Xinyuan Yu ◽  
...  
Keyword(s):  
Neurological Disorders ◽  
Temporal Cortex ◽  
New Approach ◽  
Hmg Box ◽  
Transcription Inhibitors ◽  
The Central Nervous System ◽  
And Function ◽  
Necrosis Factor

SRY-related HMG box (SOX)21, one of the most highly expressed transcription inhibitors in the central nervous system (CNS), is involved in neurogenesis-related transcription and proliferation, which are associated with certain neurological disorders. However, it is the role of SOX21 in the pathogenesis of epilepsy remains unclear. In this study, our aim was to examine the expression and function of SOX21 in patients with temporal lobe epilepsy (TLE), as well as pentylenetetrazol (PTZ)-kindled rats, and to identify the possible roles of SOX21 in epileptogenesis. We found that SOX21 localized in neurons is upregulated, especially in TLE patients. SOX21 is present in the hippocampus or adjacent temporal cortex in the PTZ-kindled epileptic rat model. In addition, the P-gpMAbNano-structured material (PNM) nanoparticles carrying anti-epileptic drugs (AEDs) were injected into the epileptic model rats using an intravenous injection. The expression of tumor necrosis factor peptide in the rats was detected to verify whether the drug-carrying nanoparticles could bypass macrophages and reach the target for treatment. We also found an interaction between SOX21 and SOX2 in PTZ-kindled rats. These results indicate that SOX21 is mainly located in neurons and may regulate the pathogenesis of epilepsy, possibly in association with SOX2. Moreover, PNM nanoparticles equipped with AEDs can reach the target through macrophages in vivo, providing a new approach for the clinical treatment of epilepsy.

scholarly journals Classification of multigene families of African swine fever viruses

2020 ◽  
Author(s):  
Zhaozhong Zhu ◽  
Huiting Chen ◽  
Yang Cao ◽  
Taijiao Jiang ◽  
Yuanqiang Zou ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Evolutionary Analysis ◽  
Dynamic Changes ◽  
Double Stranded Dna ◽  
Detailed Classification ◽  
Protein Sequence Homology ◽  
And Function

AbstractAfrican swine fever virus (ASFV) is a large and complex double-stranded DNA virus that poses serious threats to the pig industry. It is well-accepted that the multigene family (MGF) proteins are extensively distributed in ASFVs and are generally classified into five families, including MGF-100, MGF-110, MGF-300, MGF-360 and MGF-505. Most MGF proteins, however, have not been well characterized and classified within each family. To bridge this gap, this study first classified the MGF proteins into 35 groups based on protein sequence homology. A web server for classifying the MGF proteins was then established and available for free at http://www.computationalbiology.cn/MGF/home.html. Results showed that the genetic diversity of the MGF groups varied widely, mainly due to the occurrence of indels. In addition, the MGF proteins were predicted to have large structural and functional diversity, and the MGF proteins of the same MGF family tended to have similar structure, location and function. Evolutionary analysis revealed the dynamic changes of the MGF proteins in the ASFV genomes, and more than half of MGF groups were presented in all ASFV genomes, which indicated the important role of MGF proteins in ASFVs. Overall, it is expected that the work would not only provide a detailed classification for MGF proteins, but also facilitate further research on MGF proteins.

scholarly journals Dimer–dimer stacking interactions are important for nucleic acid binding by the archaeal chromatin protein Alba

2010 ◽  
Vol 427 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Clare Jelinska ◽  
Biljana Petrovic-Stojanovska ◽  
W. John Ingledew ◽  
Malcolm F. White
Keyword(s):  
Stacking Interactions ◽  
Nucleic Acid Binding ◽  
Dimer Interface ◽  
Dna And Rna ◽  
Double Stranded Dna ◽  
Helical Protein ◽  
End To End ◽  
Polypeptide Backbone

Archaea use a variety of small basic proteins to package their DNA. One of the most widespread and highly conserved is the Alba (Sso10b) protein. Alba interacts with both DNA and RNA in vitro, and we show in the present study that it binds more tightly to dsDNA (double-stranded DNA) than to either ssDNA (single-stranded DNA) or RNA. The Alba protein is dimeric in solution, and forms distinct ordered complexes with DNA that have been visualized by electron microscopy studies; these studies suggest that, on binding dsDNA, the protein forms extended helical protein fibres. An end-to-end association of consecutive Alba dimers is suggested by the presence of a dimer–dimer interface in crystal structures of Alba from several species, and by the strong conservation of the interface residues, centred on Arg59 and Phe60. In the present study we map perturbation of the polypeptide backbone of Alba upon binding to DNA and RNA by NMR, and demonstrate the central role of Phe60 in forming the dimer–dimer interface. Site-directed spin labelling and pulsed ESR are used to confirm that an end-to-end, dimer–dimer interaction forms in the presence of dsDNA.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

1999 ◽  
Vol 81 (06) ◽  
pp. 951-956 ◽  
Author(s):  
J. Corral ◽  
R. González-Conejero ◽  
J. Rivera ◽  
F. Ortuño ◽  
P. Aparicio ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Cell Types ◽  
Receptor Expression ◽  
Case Control Studies ◽  
Platelet Surface ◽  
Vitro Analysis ◽  
And Function ◽  
In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

Von Willebrand disease and Weibel-Palade bodies

2010 ◽  
Vol 30 (03) ◽  
pp. 150-155 ◽  
Author(s):  
J. W. Wang ◽  
J. Eikenboom
Keyword(s):  
Platelet Adhesion ◽  
Coagulation Factor ◽  
Von Willebrand Disease ◽  
Inflammatory Factors ◽  
Limited Data ◽  
Storage Organelle ◽  
And Function ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryVon Willebrand factor (VWF) is a pivotal haemostatic protein mediating platelet adhesion to injured endothelium and carrying coagulation factor VIII (FVIII) in the circulation to protect it from premature clearance. Apart from the roles in haemostasis, VWF drives the formation of the endothelial cell specific Weibel-Palade bodies (WPBs), which serve as a regulated storage of VWF and other thrombotic and inflammatory factors. Defects in VWF could lead to the bleeding disorder von Willebrand disease (VWD).Extensive studies have shown that several mutations identified in VWD patients cause an intracellular retention of VWF. However, the effects of such mutations on the formation and function of its storage organelle are largely unknown. This review gives an overview on the role of VWF in WPB biogenesis and summarizes the limited data on the WPBs formed by VWD-causing mutant VWF.

Sign in / Sign up

Export Citation Format

Share Document