Rio1 downregulates centromeric RNA levels to promote the timely assembly of structurally fit kinetochores.

Kinetochores assemble on centromeres via histone H3 variant CENP-A and low levels of centromere transcripts (cenRNAs). The latter are ensured by the downregulation of RNA polymerase II (RNAPII) activity, and cenRNA turnover by the nuclear exosome. Using S.

Integrating Rio1 activities discloses its nutrient-activated network in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae kinase/adenosine triphosphatase Rio1 regulates rDNA transcription and segregation, pre-rRNA processing and small ribosomal subunit maturation. Other roles are unknown. When overexpressed, human ortholog RIOK1 drives tumor growth and metastasis.

Rio1 promotes rDNA stability and downregulates RNA polymerase I to ensure rDNA segregation.

The conserved protein kinase Rio1 localizes to the cytoplasm and nucleus of eukaryotic cells. While the roles of Rio1 in the cytoplasm are well characterized, its nuclear function remains unknown. Here we show that nuclear Rio1 promotes rDNA array stability and segregation in Saccharomyces cerevisiae.

Analysis of Polo-like kinase Cdc5 in the meiosis recombination checkpoint.

In meiosis, accumulation of recombination intermediates or defects in chromosome synapsis trigger checkpoint-mediated arrest in prophase I. Such 'checkpoints' are important surveillance mechanisms that ensure temporal dependence of cell cycle events. The budding yeast Polo-like kinase, Cdc5, has been identified as a key regulator of the meiosis I chromosome segregation pattern.

Analysis of the budding yeast pH 4-7 proteome in meiosis.

Meiosis, the developmental programme generating haploid gametes from diploid precursors, requires two cell divisions and many innovations. In budding yeast, a large number of genes are expressed exclusively during meiosis while others are repressed compared to vegetative growth. Microarray analysis has shown that gene expression during meiosis is highly regulated, and has been used to classify yeast genes according to meiotic temporal expression pattern.

Nucleosome depletion activates poised RNA polymerase III at unconventional transcription sites in Saccharomyces cerevisiae.

RNA polymerase (pol) III, assisted by the transcription factors TFIIIC and TFIIIB, transcribes small untranslated RNAs, such as tRNAs. In addition to known pol III-transcribed genes, the Saccharomyces cerevisiae genome contains loci (ZOD1, ETC1-8) associated to incomplete pol III transcription complexes (Moqtaderi, Z., and Struhl, K.