We detected ENU-induced alleles of
(encoding the major facilitator superfamily domain containing 1 protein) that caused lymphopenia, splenomegaly, progressive liver pathology, and extramedullary ...hematopoiesis (EMH). MFSD1 is a lysosomal membrane-bound solute carrier protein with no previously described function in immunity. By proteomic analysis, we identified association between MFSD1 and both GLMP (glycosylated lysosomal membrane protein) and GIMAP5 (GTPase of immunity-associated protein 5). Germline knockout alleles of
,
, and
each caused lymphopenia, liver pathology, EMH, and lipid deposition in the bone marrow and liver. We found that the interactions of MFSD1 and GLMP with GIMAP5 are essential to maintain normal GIMAP5 expression, which in turn is critical to support lymphocyte development and liver homeostasis that suppresses EMH. These findings identify the protein complex MFSD1-GLMP-GIMAP5 operating in hematopoietic and extrahematopoietic tissues to regulate immunity and liver homeostasis.
We characterize the Polycomb system that assembles repressive subtelomeric domains of H3K27 methylation (H3K27me) in the yeast Cryptococcus neoformans. Purification of this PRC2-like protein complex ...reveals orthologs of animal PRC2 components as well as a chromodomain-containing subunit, Ccc1, which recognizes H3K27me. Whereas removal of either the EZH or EED ortholog eliminates H3K27me, disruption of mark recognition by Ccc1 causes H3K27me to redistribute. Strikingly, the resulting pattern of H3K27me coincides with domains of heterochromatin marked by H3K9me. Indeed, additional removal of the C. neoformans H3K9 methyltransferase Clr4 results in loss of both H3K9me and the redistributed H3K27me marks. These findings indicate that the anchoring of a chromatin-modifying complex to its product suppresses its attraction to a different chromatin type, explaining how enzymes that act on histones, which often harbor product recognition modules, may deposit distinct chromatin domains despite sharing a highly abundant and largely identical substrate—the nucleosome.
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•Cryptococcus neoformans contains subtelomeric domains of repressive H3K27me3•H3K27me3 requires a PRC2 complex containing an H3K27me-binding chromodomain subunit•Mark recognition by PRC2 functions to prevent ectopic H3K27me3 deposition•Without PRC2 mark recognition, H3K9me heterochromatin instructs H3K27me3
In the yeast Cryptococcus neoformans, the Polycomb repressive complex 2 recognizes its product, the H3K27me3 mark, to promote the specificity of H3K27me3 deposition, indicating that product recognition may function to ensure the target specificity of chromatin-modifying enzymes.
Amblyomma americanum ticks transmit more than a third of human tick-borne disease (TBD) agents in the United States. Tick saliva proteins are critical to success of ticks as vectors of TBD agents, ...and thus might serve as targets in tick antigen-based vaccines to prevent TBD infections. We describe a systems biology approach to identify, by LC-MS/MS, saliva proteins (tick = 1182, rabbit = 335) that A. americanum ticks likely inject into the host every 24 h during the first 8 days of feeding, and towards the end of feeding. Searching against entries in GenBank grouped tick and rabbit proteins into 27 and 25 functional categories. Aside from housekeeping-like proteins, majority of tick saliva proteins belong to the tick-specific (no homology to non-tick organisms: 32%), protease inhibitors (13%), proteases (8%), glycine-rich proteins (6%) and lipocalins (4%) categories. Global secretion dynamics analysis suggests that majority (74%) of proteins in this study are associated with regulating initial tick feeding functions and transmission of pathogens as they are secreted within 24-48 h of tick attachment. Comparative analysis of the A. americanum tick saliva proteome to five other tick saliva proteomes identified 284 conserved tick saliva proteins: we speculate that these regulate critical tick feeding functions and might serve as tick vaccine antigens. We discuss our findings in the context of understanding A. americanum tick feeding physiology as a means through which we can find effective targets for a vaccine against tick feeding.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Racemic 1-3-(5-methoxy-1,2,3,4-tetrahydro-1-naphtalenyl)propyl-4-phenylpiperazine (PNU-157760) was labeled with carbon-11 (t1/2= 20.4 min) as a putative radioligand for the noninvasive assessment of ...5-HT1Areceptorsin vivowith positron emission tomography (PET). The radiochemical synthesis consisted of O-methylation of desmethyl precursor with 11Cmethyl iodide in the presence of potassiumtert-butoxide in DMF. The desmethyl precursor for the radiosynthesis of 11CPNU-157760, was prepared by a convenient one-step demethylation of PNU-157760 with boron tribromide. (R,S)-O-Methyl-11C-1-3-(5-methoxy-1,2,3,4-tetrahydro-1-naphtalenyl)propyl-4-phenylpiperazine with >99% radiochemical purity was obtained in 30 min with a radiochemical yield of 10 ± 5% (EOS, nondecay corrected) and a specific radioactivity of 2.5 ± 1 Ci/μmol. Biodistribution studies in rats showed that 11CPNU-157760 readily crosses the blood–brain barrier with a maximum of brain uptake at 30 min after injection; however, the low specific-to-nonspecific binding ratioin vivoas evidenced by the low hippocampus/cerebellum uptake ratio (1.17 at 60 min postinjection) does not make 11CPNU-157760 a promising radioligand for serotonin 5-HT1Areceptors.
Positron emission tomography (PET) allows the non invasive and quantitative measurement of regional distribution of molecules labeled with positron emitting isotopes such as: nitrogen, oxygen, carbon ...and fluorine. The aim of the present paper is to review the applications of this methodology for the in vivo study of the kinetics and of the mechanism of action of drugs in humans.
Prader-Willi syndrome (PWS) is a multisystem disorder with neurobehavioral, metabolic, and hormonal phenotypes, caused by loss of expression of a paternally-expressed imprinted gene cluster. Prior ...evidence from a PWS mouse model identified abnormal pancreatic islet development with retention of aged insulin and deficient insulin secretion. To determine the collective roles of PWS genes in β-cell biology, we used genome-editing to generate isogenic, clonal INS-1 insulinoma lines having 3.16 Mb deletions of the silent, maternal- (control) and active, paternal-allele (PWS). PWS β-cells demonstrated a significant cell autonomous reduction in basal and glucose-stimulated insulin secretion. Further, proteomic analyses revealed reduced levels of cellular and secreted hormones, including all insulin peptides and amylin, concomitant with reduction of at least ten endoplasmic reticulum (ER) chaperones, including GRP78 and GRP94. Critically, differentially expressed genes identified by whole transcriptome studies included reductions in levels of mRNAs encoding these secreted peptides and the group of ER chaperones. In contrast to the dosage compensation previously seen for ER chaperones in Grp78 or Grp94 gene knockouts or knockdown, compensation is precluded by the stress-independent deficiency of ER chaperones in PWS β-cells. Consistent with reduced ER chaperones levels, PWS INS-1 β-cells are more sensitive to ER stress, leading to earlier activation of all three arms of the unfolded protein response. Combined, the findings suggest that a chronic shortage of ER chaperones in PWS β-cells leads to a deficiency of protein folding and/or delay in ER transit of insulin and other cargo. In summary, our results illuminate the pathophysiological basis of pancreatic β-cell hormone deficits in PWS, with evolutionary implications for the multigenic PWS-domain, and indicate that PWS-imprinted genes coordinate concerted regulation of ER chaperone biosynthesis and β-cell secretory pathway function.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Discarded plastic wastes in the environment are serious challenges for sustainable waste management and for the delivery of environmental and public health. Plastics in the environment become rapidly ...colonised by microbial biofilm, and importantly this so-called ‘plastisphere’ can also support, or even enrich human pathogens. The plastisphere provides a protective environment and could facilitate the increased survival, transport and dissemination of human pathogens and thus increase the likelihood of pathogens coming into contact with humans, e.g., through direct exposure at beaches or bathing waters. However, much of our understanding about the relative risks associated with human pathogens colonising environmental plastic pollution has been inferred from taxonomic identification of pathogens in the plastisphere, or laboratory experiments on the relative behaviour of plastics colonised by human pathogens. There is, therefore, a pressing need to understand whether plastics play a greater role in promoting the survival and dispersal of human pathogens within the environment compared to other substrates (either natural materials or other pollutants). In this paper, we consider all published studies that have detected human pathogenic bacteria on the surfaces of environmental plastic pollution and critically discuss the challenges of selecting an appropriate control material for plastisphere experiments. Whilst it is clear there is no ‘perfect’ control material for all plastisphere studies, understanding the context-specific role plastics play compared to other substrates for transferring human pathogens through the environment is important for quantifying the potential risk that colonised plastic pollution may have for environmental and public health.
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•Human pathogens can colonise environmental plastic pollution.•Persistence and transport of pathogens can be facilitated on plastics.•Experiments need an appropriate ‘control’ to understand potential risk.•No single control substrate can control for all relevant variables.
Although it is widely known that dams can have large impacts on the environmental and biological characteristics of downstream rivers, there is a substantial lack of studies focusing on which ...ecological processes cause longitudinal changes in biological communities downstream of reservoirs. We investigated longitudinal patterns in the total beta diversity and its replacement and richness difference components for actively (fish) and passively (phytoplankton) dispersing biological groups. Our results, obtained from a 230 km sampling stretch, demonstrated the key role played by tributaries in the downstream direction from main river impoundment, which influenced local environmental conditions and beta diversity patterns of each biological group. Both replacement and richness difference contributed to high values of total beta diversity for fish (average = 0.77) and phytoplankton (average = 0.79), but their relative importance was more associated with the replacement component for both biological groups (average = 0.45 and 0.52, respectively). Moreover, we observed clear differences between fish and phytoplankton in beta diversity patterns operating at small and broad scales, as well as in the mechanisms driving each beta diversity component. Directional dispersal-related processes and environmental filtering played a major role in shaping total beta diversity and its components for fish, while temporal factors explained considerable parts of phytoplankton beta diversity. Our findings contributed to understanding of tributary-induced heterogeneity and highlight the importance of dam-free stretches of rivers for preserving the integrity of dammed river basins.
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•We investigated longitudinal patterns of fish and phytoplankton in a dammed river.•Beta diversity was mostly contributed by species replacement for both biological groups.•Tributaries tended to be environmentally and compositionally different from main river sites.•Differences found showed that multiple taxa are recommended in assessing human disturbance.•Preserving dam-free stretches of rivers should be a priority for the integrity of dammed rivers.
Heart failure is a leading cause of mortality and morbidity in the developed world, partly because mammals lack the ability to regenerate heart tissue. Whether this is due to evolutionary loss of ...regenerative mechanisms present in other organisms or to an inability to activate such mechanisms is currently unclear. Here we decipher mechanisms underlying heart regeneration in adult zebrafish and show that the molecular regulators of this response are conserved in mammals. We identified miR-99/100 and Let-7a/c and their protein targets smarca5 and fntb as critical regulators of cardiomyocyte dedifferentiation and heart regeneration in zebrafish. Although human and murine adult cardiomyocytes fail to elicit an endogenous regenerative response after myocardial infarction, we show that in vivo manipulation of this molecular machinery in mice results in cardiomyocyte dedifferentiation and improved heart functionality after injury. These data provide a proof of concept for identifying and activating conserved molecular programs to regenerate the damaged heart.
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•Interspecies identification of conserved heart regenerative factors•miR-99/100 and Let-7a/c regulate heart regeneration•SMARCA5 and FNTβ are critical regulators of cardiomyocyte dedifferentiation•Induced dedifferentiation of mammalian cardiomyocyte results in heart regeneration
Zebrafish have an inherent capacity to regenerate injured hearts, whereas adult mammals have lost this capacity. Izpisua Belmonte and colleagues now identify mechanisms underlying cardiac regeneration in zebrafish that are conserved yet inactive in mammals, and experimental reactivation of these effectors is sufficient to regenerate infarcted myocardium in mammals.
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