Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
1,803
result(s) for
"Sutton, Roger"
Sort by:
A family of readers : the book lover's guide to children's and young adult literature
This volume is a guide to children's and young adult literature.
Book
A de novo FBN1 variant likely causes congenital bilateral ectopia lentis in a crossbred horse
Although several inherited ocular disorders have been extensively studied in horses, few reports of equine ectopia lentis exist and no genetic investigations have been reported. Ectopia lentis in humans and other species is reported to be caused by trauma, genetic variants, and systemic diseases. The most commonly reported genetic causes are dominant alleles in
FBN1
. Here we examined a 3-day old Oldenburg x Thoroughbred colt due to concerns over bilateral ocular anomalies and hypothesized that either a recessively inherited allele or a dominant
de novo
allele was the genetic cause. Examination revealed bilateral microphakia and spherophakia with medioventral lens subluxation. Histopathology of the globes was consistent with ectopia lentis. Whole genome sequencing of the affected foal was conducted, and forty-six candidate genes were evaluated for SNVs and small INDELS. Testing both hypotheses, 82 variants were identified, of which 69 were present in publicly available data from 504 horses and not investigated further. Of the 13 remaining variants, two variants were found in 3’ UTRs (
ADAMTS17
and
OAF
), ten were intronic, and one was a coding variant located in the
FBN1
gene encoding fibrillin-1 (FBN1:p.(Ala882Val)). This variant was also computationally predicted to be deleterious to protein function, including in silico modelling of FBN1 which suggests that 882Val impacts disulfide bond formation by Van der Waals clashing in a hybrid domain of the protein. The affected foal was confirmed by Sanger sequencing to be heterozygous for this variant and his clinically unaffected dam, reportedly unaffected sire, and five paternal half-siblings were homozygous for the reference allele. Additionally, the homologous human substitution is reported to be pathogenic, causing Marfan syndrome with a dominant mode of inheritance, of which ectopia lentis is a common feature. These findings support the
de novo
hypothesis with
FBN1
:p.(Ala882Val) as the likely cause of ectopia lentis in this foal, the first genetic explanation for this condition in the horse. Given the role of
FBN1
in ectopia lentis in humans and other species,
FBN1
should be evaluated as a potential candidate when other horses with this condition are identified.
Journal Article
Fibroblast-derived prolargin is a tumor suppressor in hepatocellular carcinoma
Cancer-associated fibroblasts (CAF) are important constituents of the tumor microenvironment (TME) and are major drivers of tumorigenesis. Yet, therapies aiming at eliminating CAF have failed to cure patients. This setback has raised questions regarding whether CAF exclusively favour cancer progression, or if they may also assume tumor-suppressor functions. In the present study, we used proteomics and single cell RNA-sequencing analysis to examine the CAF landscape in hepatocellular carcinoma (HCC). We thereby unveil three major CAF populations in HCC, one of which specifically expressing the prolargin protein. This CAF subpopulation (further termed as CAF_Port) shared a strong transcriptomic signature with portal liver fibroblasts. We further show that CAF_Port deposit prolargin in the TME and that its levels are lower in tumors as compared to the peritumoral region. Mechanistically, aggressive cancer cells degraded prolargin using matrix metalloprotease activity. Survival analysis of 188 patients revealed that high prolargin protein levels correlate with good patient outcome (HR = 0.37;
p
= 0.01). In vivo, co-injection of cancer cells with fibroblasts silenced for prolargin, led to faster tumor development (5-fold;
p
= 0.01), mainly due to stronger angiogenesis. Using protein-protein interaction study and structural modelling, we further demonstrate that prolargin binds and inhibits the activity of several pro-agiogenic proteins, including hepatocyte and fibroblast growth factors. In conclusion, prolargin is angiogenesis modulator and CAF-derived tumor suppressor in HCC. Stabilizing prolargin levels in the CAF_Port subpopulation may revert their tumor-antagonizing properties, warranting exploration in further pre-clinical studies.
Journal Article
A Pyrene Maleimide with a Flexible Linker for Sampling of Longer Inter-Thiol Distances by Excimer Formation
Pyrene-containing compounds are commonly used in a number of fluorescence-based applications because they can form excited-state dimers (excimers) by stacking interaction between excited-state and ground-state monomers. Their usefulness arises from the facts that excimer formation requires close proximity between the pyrenes and that the excimer emission spectrum is very different from that of the monomers. One of many applications is to assess proximity between specific sites of macromolecules labeled with pyrenes. This has been done using pyrene maleimide, a reagent that reacts with reduced thiols of cysteines, but its use for structural studies of proteins has been rather limited. This is because the introduction of two cysteines at sufficiently close distance from each other to obtain excimer fluorescence upon labeling with pyrene maleimide requires detailed knowledge of the protein structure or extensive site-directed mutagenesis trials. We synthesized and tested a new compound with a 4-carbon methylene linker placed between the maleimide and the pyrene (pyrene-4-maleimide), with the aim of increasing the sampling distance for excimer formation and making the use of excimer fluorescence simpler and more widespread. We tested the new compound on thiol-modified oligonucleotides and showed that it can detect proximity between thiols beyond the reach of pyrene maleimide. Based on its spectroscopic and chemical properties, we suggest that pyrene-4-maleimide is an excellent probe to assess proximities between cysteines in proteins and thiols in other macromolecules, as well as to follow conformational changes.
Journal Article
Otoferlin acts as a Ca2+ sensor for vesicle fusion and vesicle pool replenishment at auditory hair cell ribbon synapses
Hearing relies on rapid, temporally precise, and sustained neurotransmitter release at the ribbon synapses of sensory cells, the inner hair cells (IHCs). This process requires otoferlin, a six C2-domain, Ca2+-binding transmembrane protein of synaptic vesicles. To decipher the role of otoferlin in the synaptic vesicle cycle, we produced knock-in mice (Otof Ala515,Ala517/Ala515,Ala517) with lower Ca2+-binding affinity of the C2C domain. The IHC ribbon synapse structure, synaptic Ca2+ currents, and otoferlin distribution were unaffected in these mutant mice, but auditory brainstem response wave-I amplitude was reduced. Lower Ca2+ sensitivity and delay of the fast and sustained components of synaptic exocytosis were revealed by membrane capacitance measurement upon modulations of intracellular Ca2+ concentration, by varying Ca2+ influx through voltage-gated Ca2+-channels or Ca2+ uncaging. Otoferlin thus functions as a Ca2+ sensor, setting the rates of primed vesicle fusion with the presynaptic plasma membrane and synaptic vesicle pool replenishment in the IHC active zone.
Journal Article
Identification of the ferredoxin interaction sites on ferredoxin-dependent glutamate synthase from Synechocystis sp. PCC 6803
Based on in silico docking methods, five amino acids in glutamate synthase (Gln-467, His-1144, Asn-1147, Arg-1162, and Trp-676) likely constitute key binding residues in the interface of a glutamate synthase:ferredoxin complex. Although all interfacial mutants studied showed the ability to form a complex under low ionic strength, these docking mutations showed significantly less ferredoxin-dependent activities, while still retaining enzymatic activity. Furthermore, isothermal titration calorimetry showed a possible 1:2 molar ratio between the wild-type glutamate synthase and ferredoxin. However, each of our interfacial mutants showed only a 1:1 complex with ferredoxin, suggesting that the mutations directly affect the glutamate synthase:ferredoxin heterodimer interface.
Journal Article
A synaptotagmin suppressor screen indicates SNARE binding controls the timing and Ca2+ cooperativity of vesicle fusion
The synaptic vesicle Ca2+ sensor Synaptotagmin binds Ca2+ through its two C2 domains to trigger membrane interactions. Beyond membrane insertion by the C2 domains, other requirements for Synaptotagmin activity are still being elucidated. To identify key residues within Synaptotagmin required for vesicle cycling, we took advantage of observations that mutations in the C2B domain Ca2+-binding pocket dominantly disrupt release from invertebrates to humans. We performed an intragenic screen for suppressors of lethality induced by expression of Synaptotagmin C2B Ca2+-binding mutants in Drosophila. This screen uncovered essential residues within Synaptotagmin that suggest a structural basis for several activities required for fusion, including a C2B surface implicated in SNARE complex interaction that is required for rapid synchronization and Ca2+ cooperativity of vesicle release. Using electrophysiological, morphological and computational characterization of these mutants, we propose a sequence of molecular interactions mediated by Synaptotagmin that promote Ca2+ activation of the synaptic vesicle fusion machinery.
Journal Article
Utility of Synechocystis sp. PCC 6803 glutaredoxin A as a platform to study high-resolution mutagenesis of proteins
Glutaredoxin from the cyanobacterium Synechocystis sp. PCC 6803 is a small protein, containing only 88 amino acids, that participates in a large number of redox reactions, serving both as an electron donor for enzyme-catalyzed reductions and as a regulator of diverse metabolic pathways. The crystal structures of glutaredoxins from several species have been solved, including the glutaredoxin A isoform from the cyanobacterium Synechocystis sp. PCC 6803. We have utilized the small size of Synechocystis glutaredoxin A and its propensity to form protein crystals that diffract to high resolution to explore a long-standing question in biochemistry; i.e., what are the effects of mutations on protein structure and function? Taking advantage of these properties, we have initiated a long-term educational project that would examine the structural and biochemical changes in glutaredoxin as a function of single-point mutational replacements. Here, we report some of the mutational effects that we have observed to date.
Journal Article
Imaging of Osteoporotic Fractures on XR, CT, and MR
The evaluation of skeletal health has progressed from diagnostic labeling (normal-low bone mass-osteoporosis) to quantifying future fracture risk. Thus, the recognition of prevalent and incident fractures has increased in importance because they influence risk assessment. Non-spinal osteoporotic fractures rarely pose diagnostic problems, although those of the proximal femur and pelvis may require computed tomography (CT) and/or magnetic resonance imaging for diagnosis. Spinal fractures remain a paradox. Whereas radiological diagnosis in general benefits increasingly from powerful diagnostic tools to examine disease, many osteoporotic spinal fractures are asymptomatic, and their recognition is often incidental to chest radiography or body CT. Moreover, there are no uniformly agreed criteria by which to decide if a vertebra is fractured. Lastly, it has become apparent that some osteoporosis treatments may themselves contribute to so-called atypical femoral fractures.
Journal Article
The use of risk indices: do they predict recurrence?
A risk index which would reliably predict the likelihood of stone recurrence in the patient with renal calculi would help the clinician to select appropriate preventative therapy. However, none of the indices developed to date combines easy applicability in usual clinical settings with sufficient predictive power to be useful to the clinician in making treatment decisions.
Journal Article