Scripta in honorem Igor Fisković: zbornik povodom sedamdesetog rođendana

The International Research Centre for Late Antiquity and the Middle Ages prepared a Festschrift in honour of one of its founders, Igor Fisković on the occassion of his 70th birthday. The Festschrift  includes works addressing the periods that Igor Fisković has dealt with most, thus reflecting the diversity of his interests, ranging from Late Antiquity to contemporary art, with key emphasis on the Late Middle Ages and early modernity. Due to the diversity and the broad period of time the texts are covering, they have been arranged more or less chronologically. The works focus mainly on the Late Middle Ages and the early modern period, Fisković’s forte and the topic of some of his best writings. There are also several texts addressing the baroque period, which was not one of the honouree’s interests, but they were written by some of his closest friends and members of the generation of his former students who have had prestigious careers. (from the Foreword)Zbornik je pripredio Međunarodni istraživački centar za kasnu antiku i srednji vijek povodom sedamdesetog rođendana jednog od svojih osnivača Igora Fiskovića. Zbornik obuhvaća radove koje pokrivaju razdoblja kojima se Igor Fisković ponajviše bavio, reflektirajući raznolikost njegovih interesa, od početne kasne antike i suvremene umjetnosti, do ključnoga naglaska na kasnom srednjem vijeku i početku modernog doba. Zbog te raznolikosti i širokog vremenskog razdoblja koje pokrivaju, radovi su poredani manje-više kronološki. Ističe se brojem radova upravo kasnosrednjovjekovno doba i početci modernoga, forte u kojem je Igor Fisković dao svoje ponajbolje radove. Uz njih je i više priloga koji pokrivaju razdoblje baroka, kojim se slavljenik nije bavio, no koji su iz pera njegovih najbliskijih prijatelja i one generacije njegovih bivših studenata koji su danas ostvarili ugledne karijere. (iz Predgovora

Scripta in honorem Igor Fisković: zbornik povodom sedamdesetog rođendana

The International Research Centre for Late Antiquity and the Middle Ages prepared a Festschrift in honour of one of its founders, Igor Fisković on the occassion of his 70th birthday. The Festschrift  includes works addressing the periods that Igor Fisković has dealt with most, thus reflecting the diversity of his interests, ranging from Late Antiquity to contemporary art, with key emphasis on the Late Middle Ages and early modernity. Due to the diversity and the broad period of time the texts are covering, they have been arranged more or less chronologically. The works focus mainly on the Late Middle Ages and the early modern period, Fisković’s forte and the topic of some of his best writings. There are also several texts addressing the baroque period, which was not one of the honouree’s interests, but they were written by some of his closest friends and members of the generation of his former students who have had prestigious careers. (from the Foreword)Zbornik je pripredio Međunarodni istraživački centar za kasnu antiku i srednji vijek povodom sedamdesetog rođendana jednog od svojih osnivača Igora Fiskovića. Zbornik obuhvaća radove koje pokrivaju razdoblja kojima se Igor Fisković ponajviše bavio, reflektirajući raznolikost njegovih interesa, od početne kasne antike i suvremene umjetnosti, do ključnoga naglaska na kasnom srednjem vijeku i početku modernog doba. Zbog te raznolikosti i širokog vremenskog razdoblja koje pokrivaju, radovi su poredani manje-više kronološki. Ističe se brojem radova upravo kasnosrednjovjekovno doba i početci modernoga, forte u kojem je Igor Fisković dao svoje ponajbolje radove. Uz njih je i više priloga koji pokrivaju razdoblje baroka, kojim se slavljenik nije bavio, no koji su iz pera njegovih najbliskijih prijatelja i one generacije njegovih bivših studenata koji su danas ostvarili ugledne karijere. (iz Predgovora

Trypanosoma cruzi Gene Expression in Response to Gamma Radiation

Trypanosoma cruzi is an organism highly resistant to ionizing radiation. Following a dose of 500 Gy of gamma radiation, the fragmented genomic DNA is gradually reconstructed and the pattern of chromosomal bands is restored in less than 48 hours. Cell growth arrests after irradiation but, while DNA is completely fragmented, RNA maintains its integrity. In this work we compared the transcriptional profiles of irradiated and non-irradiated epimastigotes at different time points after irradiation using microarray. In total, 273 genes were differentially expressed; from these, 160 were up-regulated and 113 down-regulated. We found that genes with predicted functions are the most prevalent in the down-regulated gene category. Translation and protein metabolic processes, as well as generation of precursor of metabolites and energy pathways were affected. In contrast, the up-regulated category was mainly composed of obsolete sequences (which included some genes of the kinetoplast DNA), genes coding for hypothetical proteins, and Retrotransposon Hot Spot genes. Finally, the tyrosyl-DNA phosphodiesterase 1, a gene involved in double-strand DNA break repair process, was up-regulated. Our study demonstrated the peculiar response to ionizing radiation, raising questions about how this organism changes its gene expression to manage such a harmful stress

Rab7A Is Required for Efficient Production of Infectious HIV-1

Retroviruses take advantage of cellular trafficking machineries to assemble and release new infectious particles. Rab proteins regulate specific steps in intracellular membrane trafficking by recruiting tethering, docking and fusion factors, as well as the actin- and microtubule-based motor proteins that facilitate vesicle traffic. Using virological tests and RNA interference targeting Rab proteins, we demonstrate that the late endosome-associated Rab7A is required for HIV-1 propagation. Analysis of the late steps of the HIV infection cycle shows that Rab7A regulates Env processing, the incorporation of mature Env glycoproteins into viral particles and HIV-1 infectivity. We also show that siRNA-mediated Rab7A depletion induces a BST2/Tetherin phenotype on HIV-1 release. BST2/Tetherin is a restriction factor that impedes HIV-1 release by tethering mature virus particles to the plasma membrane. Our results suggest that Rab7A contributes to the mechanism by which Vpu counteracts the restriction factor BST2/Tetherin and rescues HIV-1 release. Altogether, our results highlight new roles for a major regulator of the late endocytic pathway, Rab7A, in the late stages of the HIV-1 replication cycle

The ESCRT-0 Component HRS is Required for HIV-1 Vpu-Mediated BST-2/Tetherin Down-Regulation

The Endosomal Sorting Complexes Required for Transport (ESCRT) machinery, a highly conserved set of four hetero-oligomeric protein complexes, is required for multivesicular body formation, sorting ubiquitinylated membrane proteins for lysosomal degradation, cytokinesis and the final stages of assembly of a number of enveloped viruses, including the human immunodeficiency viruses. Here, we show an additional role for the ESCRT machinery in HIV-1 release. BST-2/tetherin is a restriction factor that impedes HIV release by tethering mature virus particles to the plasma membrane. We found that HRS, a key component of the ESCRT-0 complex, promotes efficient release of HIV-1 and that siRNA-mediated HRS depletion induces a BST-2/tetherin phenotype. This activity is related to the ability of the HIV-1 Vpu protein to down-regulate BST-2/tetherin. We found that BST-2/tetherin undergoes constitutive ESCRT-dependent sorting for lysosomal degradation and that this degradation is enhanced by Vpu expression. We demonstrate that Vpu-mediated BST-2/tetherin down-modulation and degradation require HRS (ESCRT-0) function and that knock down of HRS increases cellular levels of BST-2/tetherin and restricts virus release. Furthermore, HRS co-precipitates with Vpu and BST-2. Our results provide further insight into the mechanism by which Vpu counteracts BST-2/tetherin and promotes HIV-1 dissemination, and they highlight an additional role for the ESCRT machinery in virus release

Rôles de la protéine Rab7A dans le cycle réplicatif du VIH-1

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

L'Hypertension intracrânienne bénigne en pédiatrie (étude rétrospective de 12 cas et revue de la littérature)

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Role of Rab proteins in the formation of HIV-1 particles

International audiencen.

Role of the Endosomal ESCRT Machinery in HIV-1 Vpu-Induced Down-Regulation of BST2/Tetherin.: HRS and BST-2/Tetherin Down-Regulation

International audienceThe cellular protein "Bone marrow stromal antigen 2" (BST2 also called Tetherin, CD317, HM1.24) was identified as a major mediator of the innate immune defense against the dissemination of enveloped viruses. BST2 was shown to physically trap the de novo formed viral particles at the surface of infected cells, thereby reducing viral release. Lentiviruses have evolved specific strategies to down-regulate the expression level of BST2 from the surface of the cells and as such promote viral egress. In Human Immunodeficiency Virus-1 (HIV-1), the accessory protein Vpu counters BST2 antiviral activity. However, the cellular and molecular mechanisms involved are not fully understood. Vpu-mediated antagonism of BST2 antiviral activity seems to involve complex interplay between the viral protein and host components regulating protein turnover and vesicular trafficking. This review focuses on the interplay between Vpu and the ubiquitin/endosomal pathway in countermeasures of HIV-1 to BST2 restriction