In the fission yeast S. pombe, nuclei are actively positioned at the cell center by microtubules. Here, we show that cytoplasmic microtubules are mechanically coupled to the nuclear heterochromatin through proteins embedded in the nuclear envelope. This includes an integral outer nuclear membrane protein of the KASH family (Kms2) and two integral inner nuclear membrane proteins, the SUN-domain ...

Cytological and cytogenetic studies have previously defined the region needed for centromeric function in the Y chromosome of Drosophila melanogaster. We have identified a YAC clone that originated from this region. Molecular analysis of the YAC and genomic DNAs has allowed the description of a satellite DNA made of telomeric HeT-A- and TART-derived sequences and the construction of a long-rang...

Doxorubicin, a chemotherapeutic agent, inhibits the religation step of topoisomerase II (Top2). However, the downstream ramifications of this action are unknown. Here we performed epistasis analyses of top2 with 63 genes representing doxorubicin resistance (DXR) genes in fission yeast and revealed a subset that synergistically collaborate with Top2 to confer DXR. Our findings show that the chro...

The structure of the higher-order chromatin fiber has not been defined in detail. We have used a novel approach based on sucrose gradient centrifugation to compare the conformation of centromeric satellite DNA-containing higher-order chromatin fibers with bulk chromatin fibers obtained from the same mouse fibroblast cells. Our data show that chromatin fibers derived from the centromeric domain ...

The bimodal karyotype of pig appears to contain two types of constitutive heterochromatin, reflecting different satellite DNA families: GC-rich heterochromatin located mainly in the centromeric regions of the biarmed chromosomes, and less-GC-rich heterochromatin in the centromeric regions of the one-armed chromosomes. In order to better discriminate this constitutive heterochromatin, we treated...

In vertebrate mitosis, cohesion between sister chromatids is lost in two stages. In prophase and prometaphase, cohesin release from chromosome arms occurs under the control of Polo-like kinase 1 and Aurora B, while Shugoshin is thought to prevent removal of centromeric cohesin until anaphase. The regulatory enzymes that act to sustain centromeric cohesion are incompletely described, however. Ha...

Transcription is repressed in regions of the fission yeast genome close to centromeres, telomeres, or the silent mating-type cassettes mat2-P and mat3-M. The repression involves the chromo-domain proteins Swi6 and Clr4. We report that two other chromo-domain proteins, Chp1 and Chp2, are also important for these position effects. Chp1 showed a specificity for centromeric regions. Its essentialit...

Replication fork-associated factors promote genome integrity and protect against cancer. Mutations in the DDX11 helicase and the ESCO2 acetyltransferase also cause related developmental disorders classified as cohesinopathies. Here we generated vertebrate model cell lines of these disorders and cohesinopathies-related genes. We found that vertebrate DDX11 and Tim-Tipin are individually needed t...

Centromeres are chromosomal domains essential for genomic stability. We report here the remarkable transcriptional and epigenetic perturbations at murine centromeres in genotoxic stress conditions. A strong and selective transcriptional activation of centromeric repeats is detected within hours. This is followed by disorganization of centromeres with striking delocalization of nucleosomal CENP-...

RNA is involved in a variety of chromatin modification events, ranging from large-scale structural rearrangements to subtle local affects. Here, we extend the evidence for RNA-chromatin interactions to the centromere core. The data indicate that maize centromeric retrotransposons (CRMs) and satellite repeats (CentC) are not only transcribed, but that nearly half of the CRM and CentC RNA is tigh...