Andoniou CE  Fleming P  Sutton VR  Trapani JA  Degli-Esposti MA 《Immunology and cell biology》2011,89(4):540-548

Destruction of target cells by cytotoxic T lymphocytes (CTLs) or natural killer (NK) cells requires the coordinated action of the pore forming protein perforin (Pfp) and the granzyme (Gzm) family of serine proteases. The activation of a number of serine proteases, including GzmA and B, is predominately mediated by cathepsin C (CatC). Deficiencies in CatC-null mice were therefore expected to replicate the defects observed in GzmAB-deficient mice. We have previously determined that GzmAB-deficient mice exhibit increased susceptibility to murine cytomegalovirus (MCMV) infection. Here, we have compared the ability of CatC(-/-) mice to control MCMV infection with that of GzmAB-deficient animals. We found that CatC(-/-) mice have organ-specific defects in the ability to control MCMV replication, a phenotype that is distinct to that observed in GzmAB(-/-) mice. Significantly, the cytolytic function of CatC-deficient NK cells and CTLs elicited during infection was indistinguishable from that of wild-type cells. Hence, CatC is involved in limiting MCMV replication; however, this effect is independent of its role in promoting effector cytolytic activity. These data provide evidence for a novel and unexpected role of CatC during viral infection.  相似文献   

    

Tuane C. R. G. Vieira;Caroline A. Barros;Renato Domingues;Tiago Fleming Outeiro; 《Journal of neurochemistry》2024,168(8):1625-1639

The discovery of prions has challenged dogmas and has revolutionized our understanding of protein-misfolding diseases. The concept of self-propagation via protein conformational changes, originally discovered for the prion protein (PrP), also applies to other proteins that exhibit similar behavior, such as alpha-synuclein (aSyn), a central player in Parkinson's disease and in other synucleinopathies. aSyn pathology appears to spread from one cell to another during disease progression, and involves the misfolding and aggregation of aSyn. How the transfer of aSyn between cells occurs is still being studied, but one important hypothesis involves receptor-mediated transport. Interestingly, recent studies indicate that the cellular prion protein (PrPC) may play a crucial role in this process. PrPC has been shown to act as a receptor/sensor for protein aggregates in different neurodegenerative disorders, including Alzheimer's disease and amyotrophic lateral sclerosis. Here, we provide a comprehensive overview of the current state of knowledge regarding the interaction between aSyn and PrPC and discuss its role in synucleinopathies. We examine the properties of PrP and aSyn, including their structure, function, and aggregation. Additionally, we discuss the current understanding of PrPC's role as a receptor/sensor for aSyn aggregates and identify remaining unanswered questions in this area of research. Ultimately, we posit that exploring the interaction between aSyn and PrPC may offer potential treatment options for synucleinopathies.  相似文献   

    

Shanghua Fan  Defeng Li  Joy Fleming  Yuan Hong  Tao Chen  Lin Zhou  Lijun Bi  Dacheng Wang  Xianen Zhang  Guanjun Chen 《Acta Crystallographica. Section F, Structural Biology Communications》2014,70(10):1372-1375

7‐Keto‐8‐aminopelargonic acid synthase (KAPA synthase; BioF) is an essential enzyme for mycobacterial growth that catalyses the first committed step in the biotin‐synthesis pathway. It is a pyridoxal 5′‐phosphate (PLP)‐dependent enzyme and is a potential drug target. Here, the cloning, expression, purification and crystallization of KAPA synthase from Mycobacterium smegmatis (MsBioF) and the characterization of MsBioF crystals using X‐ray diffraction are described. The crystals diffracted to 2.3 Å resolution and belonged to the monoclinic space group P2₁, with unit‐cell parameters a = 70.88, b = 91.68, c = 109.84 Å, β = 97.8°. According to the molecular weight of MsBioF, the unit‐cell parameters and the self‐rotation function map, four molecules are present in each asymmetric unit with a V_M value of 2.06 ų Da⁻¹ and a solvent content of 40.20%.  相似文献   

    

Sarah E. Yeates  Sigurd Einum  Ian A. Fleming  William V. Holt  Matthew J.G. Gage 《Evolutionary Applications》2014,7(4):493-505

Adaptations at the gamete level (a) evolve quickly, (b) appear sensitive to inbreeding and outbreeding and (c) have important influences on potential to reproduce. We apply this understanding to problems posed by escaped farm salmon and measure their potential to reproduce in the wild. Farm Atlantic salmon (Salmo salar) are a threat to biodiversity, because they escape in large numbers and can introgress, dilute or disrupt locally adapted wild gene pools. Experiments at the whole fish level have found farm reproductive potential to be significant, but inferior compared to wild adults, especially for males. Here, we assess reproductive performance at the gamete level through detailed in vitro comparisons of the form, function, fertility, compatibility and competitiveness of farm versus wild Atlantic salmon sperm and eggs, in conditions mimicking the natural gametic microenvironment, using fish raised under similar environmental conditions. Despite selective domestication and reduced genetic diversity, we find functional equivalence in all farm fish gamete traits compared with their wild ancestral strain. Our results identify a clear threat of farm salmon reproduction with wild fish and therefore encourage further consideration of using triploid farm strains with optimized traits for aquaculture and fish welfare, as triploid fish remain reproductively sterile following escape.  相似文献   

    

Zhirong Li  Tae Kyu Ahn  Thomas J. Avenson  Matteo Ballottari  Jeffrey A. Cruz  David M. Kramer  Roberto Bassi  Graham R. Fleming  Jay D. Keasling  Krishna K. Niyogi 《The Plant cell》2009,21(6):1798-1812

Plants protect themselves from excess absorbed light energy through thermal dissipation, which is measured as nonphotochemical quenching of chlorophyll fluorescence (NPQ). The major component of NPQ, qE, is induced by high transthylakoid ΔpH in excess light and depends on the xanthophyll cycle, in which violaxanthin and antheraxanthin are deepoxidized to form zeaxanthin. To investigate the xanthophyll dependence of qE, we identified suppressor of zeaxanthin-less1 (szl1) as a suppressor of the Arabidopsis thaliana npq1 mutant, which lacks zeaxanthin. szl1 npq1 plants have a partially restored qE but lack zeaxanthin and have low levels of violaxanthin, antheraxanthin, and neoxanthin. However, they accumulate more lutein and α-carotene than the wild type. szl1 contains a point mutation in the lycopene β-cyclase (LCYB) gene. Based on the pigment analysis, LCYB appears to be the major lycopene β-cyclase and is not involved in neoxanthin synthesis. The Lhcb4 (CP29) and Lhcb5 (CP26) protein levels are reduced by 50% in szl1 npq1 relative to the wild type, whereas other Lhcb proteins are present at wild-type levels. Analysis of carotenoid radical cation formation and leaf absorbance changes strongly suggest that the higher amount of lutein substitutes for zeaxanthin in qE, implying a direct role in qE, as well as a mechanism that is weakly sensitive to carotenoid structural properties.  相似文献   

  总被引：6，自引：1，他引：5  

J Tang  N Abovich  M L Fleming  B Seraphin    M Rosbash 《The EMBO journal》1997,16(13):4082-4091

U1C is one of the three human U1 small nuclear ribonucleoprotein (snRNP)-specific proteins and is important for efficient complex formation between U1 snRNP and the pre-mRNA 5' splice site. We identified a hypothetical open reading frame in Saccharomyces cerevisiae as the yeast homolog of the human U1C protein. The gene is essential, and its product, YU1C, is associated with U1 snRNP. YU1C depletion gives rise to normal levels of U1 snRNP and does not have any detectable effect on U1 snRNP assembly. YU1C depletion and YU1C ts mutants affect pre-mRNA splicing in vivo, and extracts from these strains form low levels of commitment complexes and spliceosomes in vitro. These experiments indicate a role for YU1C in snRNP function. Structure probing with RNases shows that only the U1 snRNA 5' arm is hypersensitive to RNase I digestion when YU1C is depleted. Similar results were obtained with YU1C ts mutants, indicating that U1C contributes to a proper 5' arm structure prior to its base pairing interaction with the pre-mRNA 5' splice site.  相似文献   

    

James E. Fleming  Greg S. Spicer  Roger C. Garrison  Michael R. Rose 《Genetica》1993,91(1-3):183-198

Five populations ofDrosophila melanogaster that had been selected for postponed aging were compared with five control populations using two-dimensional protein gel electrophoresis. The goals of the study were to identify specific proteins associated with postponed aging and to survey the population genetics of the response to selection. A total of 321 proteins were resolvable per population; these proteins were scored according to their intensity. The resulting data were analyzed using resampling, combinatoric, and maximum parsimony methods. The analysis indicated that the populations with postponed aging were different from their controls with respect to specific proteins and with respect to the variation between populations. The populations selected for postponed aging were more heterogeneous between populations than were the control populations. Maximum parsimony trees separate the selected populations, as a group, from their controls, thereby exhibiting a homoplastic pattern.  相似文献   

    

Therese Mandel  Andrew J. Fleming  Rolf Krähenbühl  Cris Kuhlemeier 《Plant molecular biology》1995,29(5):995-1004

The NeIF-4A10 gene belongs to a family of at least ten genes, all of which encode closely related isoforms of translation initiation factor 4A. The promoter region of NeIF-4A10 was sequenced, and four mRNA 5 ends were determined. Deletions containing 2750, 689 and 188 bp of untranscribed upstream DNA were fused to the GUS reporter gene and introduced into transgenic tobacco. The three constructs mediated GUS expression in all cells of the leaf, stem and shoot apical meristem. Control experiments using in situ hybridization and tissue printing indicated that the observed GUS expression matches the expression patterns of NeIF-4A mRNA and protein. This detailed analysis at the level of mRNA, protein and reporter gene expression shows that NeIF-4A10 is an ideal constitutively expressed control gene. We argue that inclusion of such a control gene in experiments dealing with specifically expressed genes is in many cases essential for the correct interpretation of observed expression patterns.  相似文献   

    

Alan D. Fleming  Ryuzo Yanagimachi  Hiroko Yanagimachi 《Molecular reproduction and development》1979,2(4):357-366

Mature unfertilized ova from superovulated hamsters were freed from all investments and frozen at ?50°C. They were cooled at about 1°C/min to 0°C then at 0.8° to 0.6°C/min to ?50°C. At 0°C, dimethyl sulfoxide was added to a final concentration of 1.25 M. The ova were stored at ?50°C for up to four months. Thawing was performed at 2–4°C/min and followed by several washes with insemination medium. Approximately 90% of the ova were normal in appearance after thawing. The frozen and thawed ova with normal appearance could be penetrated by hamster or human spermatozoa at a rate comparable to unfrozen controls. The ability of hamster ova to tolerate storage at a relatively convenient temperature (?50°C) for long periods (tested for up to four months) makes possible their shipment at low cost to institutions lacking this resource. There they can be used for basic biological studies of sperm–egg interaction or in the clinical assessment of human sperm quality.  相似文献   

    

Elizabeth Boyd  Usama Abdulla  Ian Donald  J. E. E. Fleming  A. J. Hall  M. A. Ferguson-Smith 《BMJ (Clinical research ed.)》1971,2(5760):501-502

Human lymphocyte cultures were examined for chromosome damage after exposure to ultrasound. Control and treated slides were scored “blind” and showed no evidence of damage due to ultrasound. Neither was there evidence of chromosome damage in blood cultures from six infants whose mothers had ultrasound during pregnancy when compared with that from six infants whose mothers had not. Our results suggest that if diagnostic ultrasound causes chromosome damage it does so with less frequency than acceptable levels of diagnostic x-irradiation.  相似文献