Hierarchical TAF1-dependent co-translational assembly of the basal transcription factor TFIID.

Large heteromeric multiprotein complexes play pivotal roles at every step of gene expression in eukaryotic cells. Among them, the 20-subunit basal transcription factor TFIID nucleates the RNA polymerase II preinitiation complex at gene promoters. Here, by combining systematic RNA-immunoprecipitation (RIP) experiments, single-molecule imaging, proteomics and structure-function analyses, we show that human TFIID biogenesis occurs co-translationally.

Hierarchical TAF1-dependent co-translational assembly of the basal transcription factor TFIID.

Large heteromeric multiprotein complexes play pivotal roles at every step of gene expression in eukaryotic cells. Among them, the 20-subunit basal transcription factor TFIID nucleates RNA polymerase II preinitiation complex at gene promoters. Here, by combining systematic RNA-immunoprecipitation (RIP) experiments, single-molecule imaging, proteomics and structure-function analyses, we show that TFIID biogenesis occurs co-translationally.

Update on Distribution and Genetic Variability of Strains in Bulgaria.

Field surveys for (PPV) infection were conducted in stone fruit orchards all over Bulgaria. In total, 1168 out of 3020 leaf samples from cultivated spp. and wildly growing trees reacted positive for PPV in DASI-ELISA with the universal monoclonal antibody (MAb) 5B.

Co-translational assembly of mammalian nuclear multisubunit complexes.

Cells dedicate significant energy to build proteins often organized in multiprotein assemblies with tightly regulated stoichiometries. As genes encoding subunits assembling in a multisubunit complex are dispersed in the genome of eukaryotes, it is unclear how these protein complexes assemble. Here, we show that mammalian nuclear transcription complexes (TFIID, TREX-2 and SAGA) composed of a large number of subunits, but lacking precise architectural details are built co-translationally.

Mutations on the DNA binding surface of TBP discriminate between yeast TATA and TATA-less gene transcription.

Most RNA polymerase (Pol) II promoters lack a TATA element, yet nearly all Pol II transcription requires TATA binding protein (TBP). While the TBP-TATA interaction is critical for transcription at TATA-containing promoters, it has been unclear whether TBP sequence-specific DNA contacts are required for transcription at TATA-less genes. Transcription factor IID (TFIID), the TBP-containing coactivator that functions at most TATA-less genes, recognizes short sequence-specific promoter elements in metazoans, but analogous promoter elements have not been identified in Saccharomyces cerevisiae.

Mediterranean and central-eastern European countries host viruses of two different clades of plum pox virus strain M.

The genetic diversity of plum pox virus strain M (PPV-M) was assessed by analyzing 28 isolates collected in 8 European countries. Two genomic fragments spanning the (Cter)P3-6K1-(Nter)CI coding region as well as the full coat protein coding region were sequenced directly from PCR products. Phylogenetic analysis showed that the geographical origin of the collected isolates was clearly associated with two different PPV-M clades.

Identification and Characterization of a Novel Tobamovirus from Tropical Soda Apple in Florida.

Foliar symptoms suggestive of virus infection were recently observed on the noxious weed tropical soda apple (Solanum viarum) in Florida. An agent was mechanically transmitted to Nicotiana benthamiana, and virions were isolated from systemically infected leaves. Rod-shaped particles ~300 nm in length were observed in the partially purified preparations by electron microscopy.

Transmission, In Planta Distribution, and Management of Hibiscus latent Fort Pierce virus, a Novel Tobamovirus Isolated from Florida Hibiscus.

Three aspects of the infection process of a new tobamovirus species, Hibiscus latent Fort Pierce virus, recently isolated from hibiscus in Florida, were examined: (i) transmission efficiency of rub-, slash-, and cut-inoculation for two hibiscus cultivars, Pink Versicolor and Brilliant Red; (ii) distribution within infected hibiscus plants; and (iii) treatments to prevent infection during plant propagation and pruning. Rub-, slash-, and cut-inoculation methods were all effective and yielded infection rates of 66, 74, and 70%, respectively, in Pink Versicolor and 50, 56, and 38%, respectively, in Brilliant Red. Analysis of virus distribution in infected plants over time revealed that the virus moved from the place of inoculation to the roots and then toward the bottom (oldest) leaves of the plants.

Comparison of Detection Methods for a Novel Tobamovirus Isolated from Florida Hibiscus.

A novel tobamovirus recently was isolated from hibiscus in Florida. Serological and molecular methods, including enzyme-linked immunosorbent assay (ELISA), dot-blot immunoassay (DBIA), tissue-blot immunoassay (TBIA), and immunocapture reverse-transcription poly-merase chain reaction (IC-RT-PCR) were compared to evaluate their usefulness for diagnosis of this virus. Each method was tested with partially purified virus preparations and tissue samples from infected hibiscus and Chenopodium quinoa plants.

Biological and Molecular Characterization of a Novel Tobamovirus with a Unique Host Range.

Tobamoviruses are among the best characterized and most studied plant viruses. Three subgroups of tobamoviruses correspond to viral genome sequence and host range to include those viruses infecting (i) solanaceous plants, (ii) brassicas, or (iii) cucurbits or legumes. We isolated a virus from Florida landscape plantings of the malvaceous plant hibiscus (Hibiscus rosasinensis) that appears to be a tobamovirus based upon its virion morphology, genome organization, and coat protein sequence.