BACKGROUND Ribosomal deficits are documented in mild cognitive impairment (MCI), which often represents an early stage Alzheimer's disease (AD), as well as in advanced AD. The nucleolar rRNA genes (rDNA), transcription of which is critical for ribosomal biogenesis, are regulated by epigenetic silencing including promoter CpG methylation. METHODOLOGY/PRINCIPAL FINDINGS To assess whether CpG me...

The 16S rDNA, 16S-23S rDNA-ITS, cpcBA-IGS, mcy gene and several polysaccharide biosynthesis-related genes (epsL and TagH) were analyzed along with the identification of the morphology of Microcystis colonies collected in Lake Taihu in 2014. M. wesenbergii colonies could be distinguished directly from other colonies using espL. TagH divided all of the samples into two clusters but failed to dist...

BACKGROUND DNA barcoding has recently been proposed as a promising tool for the rapid species identification in a wide range of animal taxa. Two broad methods (distance and monophyly-based methods) have been used. One method is based on degree of DNA sequence variation within and between species while another method requires the recovery of species as discrete clades (monophyly) on a phylogenet...

Background:The zinc-finger X linked (ZFX) gene encodes a transcription factor that acts as a regulator of self-renewal of stem cells. Due to the role of ZFX in cell growth, understanding ZFX protein-protein interactions helps to clarify its proper biological functions in signaling pathways. The aim of this study is to define ZFX protein-protein interactions and the role of ZFX in cell growth. ...

The Arabidopsis thaliana genome comprises around 1,000 copies of 5S rRNA genes encoding both major and minor 5S rRNAs. In mature wild-type leaves, the minor 5S rRNA genes are silent. Using different mutants of DNA methyltransferases (met1, cmt3 and met1 cmt3), components of the RNAi pathway (ago4) or post-translational histone modifier (hda6/sil1), we show that the corresponding proteins are ne...

SWI/SNF is a chromatin remodeling complex that affects transcription initiation and elongation by RNA polymerase II. Here we report that SWI/SNF also plays a role in transcription by RNA polymerase I (Pol I) in Saccharomyces cerevisiae. Deletion of the genes encoding the Snf6p or Snf5p subunits of SWI/SNF was lethal in combination with mutations that impair Pol I transcription initiation and el...

Fibre-FISH (fluorescence in situ hybridization) has not been used in filamentous fungi before to the authors' knowledge. In this study, this technique was applied to a filamentous ascomycete, Cochliobolus heterostrophus, to visualize the organization of the rRNA gene clusters (rDNA). Using protoplasts embedded in agarose, DNA fibres were released from interphase nuclei and extended on a glass s...

Using a system of interspecies hybrids, trihybrids, and recombinants with varying proportions of genomes from three distinct Xenopus species, we provide evidence for de novo epigenetic silencing of paternal 45 S ribosomal ribonucleic acid (rRNA) genes and their species-dependent expression dominance that escapes transcriptional inactivation after homologous recombination. The same pattern of im...

JCB • VOLUME 181 • NUMBER 5 • 2008 714 rDNA si lencing saves starving cel ls H istone methylation at ribosomal genes saves cells when sugar is in short supply, say Akiko Murayama, Junn Yanagisawa (University of Tsukuba, Japan), and colleagues. The team identifi es multiple parts of the machinery that links energy levels to epigenetics. Ribosome biogenesis demands lots of energy, and rDNA transc...

The primary function of the nucleolus is as the site of ribosome subunit biogenesis in eukaryotic cells. Nucleoli reassemble at the end of mitosis around the tandemly repeated clusters of rDNA genes forming a subnuclear compartment that locally concentrates the dedicated transcription and processing machineries that are responsible for generating ribosome subunits. The process of assembling a r...