In Trypanosoma brucei, transcription resistant to the mushroom toxin alpha-amanitin is not restricted to the rRNA genes (rDNA), as in higher eukaryotes, but extends to genes encoding the major cell surface proteins variant surface glycoprotein (VSG) and procyclin or procyclic acidic repetitive protein (PARP). Here, we report the development of a homologous cell extract from procyclic T. brucei ...

Three nuclear genes, lsu-rDNA (encoding nuclear large subunit rDNA), ITS (encoding the rDNA internal transcribed spacers and 5.8 S rDNA) and rpb2 (encoding the second largest subunit of RNA polymerase II), and the mitochondrial gene atp6 (encoding the sixth subunit of ATP synthase), were sequenced from all recognized Sparassis lineages. Sparassis latifolia sp. nov. from boreal coniferous forest...

Increased human activities and environmental changes may lead to genetic diversity variations of Cladocerans in water. Daphnia pulex are distributed throughout the world and often regarded as a model organism. The 16S rDNA, cytochrome c oxidase subunit I (COI), and 18S genes were used as molecular marks. The genetic diversity and phylogeny of D. pulex obtained from 10 water bodies in the middle...

In addition to rusts, the subphylum Pucciniomycotina (Basidiomycota) includes a large number of unicellular or dimorphic fungi which are usually studied as yeasts. Ribosomal DNA sequence analyses have shown that the current taxonomic system of the pucciniomycetous yeasts which is based on phenotypic criteria is not concordant with the molecular phylogeny and many genera are polyphyletic. Here w...

We combine a morphological description with a multigene analysis to assess the phylogenetic placement of a poorly known amoeboid taxon Corallomyxa within the eukaryotic tree of life. A detailed morphological analysis including transmission electron microscopy and light microscopy of Corallomyxa sp. ATCC 50975 demonstrates that this isolate is a new species, herein designated, Corallomyxa tenera...

Abstract Stem and progenitor cells undergo a global elevation of nascent transcription, or hypertranscription, during key developmental transitions involving rapid cell proliferation. The chromatin remodeler Chd1 mediates hypertranscription in pluripotent but its mechanism action remains poorly understood. Here we report novel role for protecting genome integrity at promoter regions by preventi...

The question of whether the Ybb- chromosome contains ribosomal genes has been examined by using Southern blot analysis and comparing rDNA hybridization patterns for X/X and X/Ybb- DNA. The results demonstrate that the Ybb- chromosome contains sequences that hybridize to an rDNA probe under stringent conditions. Differential hybridization of some of these sequences with DNAs corresponding to dif...

Nucleoli are the morphological expression of the activity of a defined set of chromosomal segments bearing rRNA genes. The topological distribution and composition of the intranucleolar chromatin as well as the definition of nucleolar structures in which enzymes of the rDNA transcription machinery reside have been investigated in mammalian cells by various immunogold labelling approaches at the...

Changes in the spatial positioning of genes within the mammalian nucleus have been associated with transcriptional differences and thus have been hypothesized as a mode of regulation. In particular, the localization of genes to the nuclear and nucleolar peripheries is associated with transcriptional repression. However, the mechanistic basis, including the pertinent cis- elements, for such asso...

Cloned ribosomal DNA (rDNA) from mouse, which contains the initiation site of 45S pre-rRNA transcription and 5' flanking sequences, has been used as the template in an in vitro transcription system. In the presence of extracts from rapidly growing Ehrlich ascites cells, RNA polymerase I initiates specifically in that region of purified rDNA where the 5' end of 45S rRNA has been mapped. This is ...