Peroxisomal very long-chain fatty acid transport is targeted by herpesviruses and the antiviral host response

Very long-chain fatty acids (VLCFA) are critical for human cytomegalovirus replication and accumulate upon infection. Here, we used Epstein-Barr virus (EBV) infection of human B cells to elucidate how herpesviruses target VLCFA metabolism. Gene expression profiling revealed that, despite a general induction of peroxisome-related genes, EBV early infection decreased expression of the peroxisomal VLCFA transporters ABCD1 and ABCD2, thus impairing VLCFA degradation. The mechanism underlying ABCD1 and ABCD2 repression involved RNA interference by the EBV-induced microRNAs miR-9-5p and miR-155, respectively, causing significantly increased VLCFA levels. Treatment with 25-hydroxycholesterol, an antiviral innate immune modulator produced by macrophages, restored ABCD1 expression and reduced VLCFA accumulation in EBV-infected B-lymphocytes, and, upon lytic reactivation, reduced virus production in control but not ABCD1-deficient cells. Finally, also other herpesviruses and coronaviruses target ABCD1 expression. Because viral infection might trigger neuroinflammation in X-linked adrenoleukodystrophy (X-ALD, inherited ABCD1 deficiency), we explored a possible link between EBV infection and cerebral X-ALD. However, neither immunohistochemistry of post-mortem brains nor analysis of EBV seropositivity in 35 X-ALD children supported involvement of EBV in the onset of neuroinflammation. Collectively, our findings indicate a previously unrecognized, pivotal role of ABCD1 in viral infection and host defence, prompting consideration of other viral triggers in cerebral X-ALD

Seed Dispersal Distances by Ants Increase in Response to Anthropogenic Disturbances in Australian Roadside Environments

Ants provide a common dispersal vector for a variety of plants in many environments through a process known as myrmecochory. The efficacy of this dispersal mechanism can largely determine the ability of species to track changes in habitat availability caused by ongoing land-use and associated disturbances, and can be critical for population gene flow and persistence. Field studies were conducted in a typical fragmented agricultural landscape in southern NSW, Australia, to investigate the extent to which dispersal services by ants are influenced by anthropogenic disturbances associated with roadwork activities (i.e., soil disturbance as the result of grading of roads). Observational experiments were performed in road segments that were divided into disturbed and non-disturbed zones, where Acacia pycnantha seeds were offered at multiple bait stations and monitored. For combined species, the mean dispersal distance recorded in the disturbed zone (12.2 m) was almost double that recorded in the non-disturbed zone (5.4 m) for all roadside sites. Our findings show that myrmecochory is an unevenly diffuse mutualism, where few ant species contributed to much of the dispersal of seeds. Iridomyrmex purpureus was responsible for all seed dispersal distances >17 m, where a maximum of 120 m in disturbed, vs. 69 m in non-disturbed zones, was recorded. Rhytidoponera metallica and Melophorus bruneus were important seed dispersers in non-disturbed and disturbed zones, respectively. In general, large bodied ants tended to move more seeds to longer distances in disturbed zones, as opposed to non-disturbed zones, where smaller bodied species carried out a greater percentage of short distance dispersals (<1 m). We also recorded secondary dispersal events from nests by I. purpureus, a phenomenon previously not quantified. Infrequent, long distance dispersal to suitable sites may be highly important for seedling recruitment in disturbed or modified habitats in otherwise highly fragmented rural environments

U1C (TbU1C): a U1 snRNP-specific component binding specifically to the 5′ terminal sequence of U1 snRNA

<p><b>Copyright information:</b></p><p>Taken from "U1 small nuclear RNP from : a minimal U1 snRNA with unusual protein components"</p><p>Nucleic Acids Research 2005;33(8):2493-2503.</p><p>Published online 29 Apr 2005</p><p>PMCID:PMC1087902.</p><p>© The Author 2005. Published by Oxford University Press. All rights reserved</p> () ClustalW alignment of the protein sequences for the newly identified U1C homologs from , and , in comparison with the human U1C sequence. The conserved CH-type Zn finger within the boxed sequence is highlighted by large-size letters; asterisks indicate absolutely conserved amino acid positions. Accession numbers (GeneDB): (Tb10.70.5640), (Tc00.1047053511367.354) and (LmjF21.0320); human U1C (P09234). () Extract was prepared from a cell line, which stably expresses TAP-tagged TbU1C protein, and used to affinity-purify TAP-tagged complexes. Purification was followed by analyzing copurifying RNAs by northern blotting, using a mixed snRNA probe (snRNA positions indicated on the right). , DIG marker V (Roche). Lane 1, 1% of input; lane 2, 10% of IgG-selected and TEV-released material. Affinity-purified complexes were then immunoprecipitated with NIS (lane 3), anti TbU1-70K (lane 4) or anti-Sm antibodies (lane 5), using 30% for each immunoprecipitation. () TbU1C protein binds specifically to the 5′ terminal sequence of U1 snRNA. GST TbU1C protein was incubated with P-labeled full-length U1 snRNA (lanes 1 and 2) and various U1 snRNA derivatives: U1 Δstem–loop (lanes 3 and 4), U1 Δ5′(1–14) (lanes 5, 6), U1 Δ5′(1–30) (lanes 7 and 8), U1 5′ stem–loop (lanes 9 and 10), U1 5′(1–14) (lanes 11 and 12) or a 17mer control RNA (lanes 13 and 14). In each case, 10% of the input () and the total GST pull-down material () were analyzed

Protein–protein interactions in the trypanosome U1 snRNP: TbU1-70K interacts with both TbU1C and TbU1-24K

<p><b>Copyright information:</b></p><p>Taken from "U1 small nuclear RNP from : a minimal U1 snRNA with unusual protein components"</p><p>Nucleic Acids Research 2005;33(8):2493-2503.</p><p>Published online 29 Apr 2005</p><p>PMCID:PMC1087902.</p><p>© The Author 2005. Published by Oxford University Press. All rights reserved</p> () GST-fusion proteins of TbU1C, TbU1-24K and TbU1-70K, as well as GST alone as a control were immobilized on glutathione-Sepharose. Corresponding aliquots of immobilized proteins were analyzed for their protein content by SDS–PAGE and Coomassie staining. The arrows point to the proteins listed above the lanes. , protein marker (in kDa). () Immobilized GST proteins (as indicated above the lanes) were incubated with S-labeled TbU1C (lanes 1–4), TbU1-24K (lanes 5–8) or TbU1-70K (lanes 9–12). After washing, bound proteins were recovered and analyzed by SDS–PAGE and fluorography. The arrows point to the respective S-labeled proteins

TbU1-70K is a U1 snRNP-specific protein and binds specifically to the 5′ loop sequence of U1 snRNA

<p><b>Copyright information:</b></p><p>Taken from "U1 small nuclear RNP from : a minimal U1 snRNA with unusual protein components"</p><p>Nucleic Acids Research 2005;33(8):2493-2503.</p><p>Published online 29 Apr 2005</p><p>PMCID:PMC1087902.</p><p>© The Author 2005. Published by Oxford University Press. All rights reserved</p> () Comparison of the domain structures of (Tb08.4A8.530) and the human U1-70K (A25707) proteins. () Western blot analysis of U1 snRNP proteins. U1 snRNPs were affinity-purified from extract by a 2′--methyl RNA antisense oligonucleotide, protein was prepared and analyzed by SDS–PAGE and western blotting, using polyclonal rabbit antibodies against TbU1-70K (U1-70K) or non-immune serum (NIS). The arrow points to the immunostained TbU1-70K band of apparent molecular weight 40 kDa. Protein markers are on the right (in kDa). () U1 snRNA is specifically coprecipitated from extract by anti-Tb U1-70 antibodies. Immunoprecipitations were carried out from extract, using NIS, or with antibodies against the TbU1-70K protein (U1-70K) or against the trypanosome Sm proteins (Sm). RNA was purified from the immunoprecipitates and analyzed by 3′ end labeling with [P]pCp. The positions of the SL RNA and snRNAs are marked on the right. , P-labeled pBR322/HpaII markers. () RNA from the same immunoprecipitates was also analyzed by primer extension with a U1-specific oligonucleotide. In addition, RNA from a 10% aliquot of the input was included; the positions of the primer () and the U1-specific primer-extension product (U1) are marked on the right. , P-labeled pBR322/HpaII markers. () P-labeled U1 snRNA and mutant derivatives [as indicated above the lanes; see (F)] were transcribed and incubated with GST-TbU1-70K, followed by GST pull-down. For each reaction, 10% of the input () and the total precipitated material () were analyzed. , P-labeled pBR322/HpaII markers. () Sequences and proposed secondary structures of the U1 snRNA and its mutant derivatives. The boxed sequence in the U1 snRNA indicates the Sm site; the two arrows indicate a potential second stem–loop. Below, the sequences of the stem–loop derivatives are given; the circled nucleotides mark the two positions in the human loop that differ from the sequence, and the single-nucleotide mutation (A21) in the mutant human loop