Biomedical subjects

Alison Pidoux

Publications and source records attributed to Alison Pidoux.

6 recordsLinked to original sources

PubMed2025

ChIPmentation for Epigenomic Analysis in Fission Yeast.

Histone modifications and transcription factor-DNA interactions regulate vital processes such as transcription, recombination, repair, and accurate chromosome segregation. Chromatin immunoprecipitation followed by sequencing (ChIP-Seq) has been instrumental in studying genome-wide distribution of DNA-bound or chromatin-associated factors and histone posttranslational modifications (PTMs). Here, we describe a ChIPmentation protocol adapted for fission yeast, Schizosaccharomyces pombe. This method merges Tn5 mediated tagmentation with existing ChIP protocols, resulting in lower sample input requirements with significant reduction in hands-on time and sample preparation costs.

Schizosaccharomyces↗

PubMed2006

Fta2, an essential fission yeast kinetochore component, interacts closely with the conserved Mal2 protein.

The fission yeast multiprotein-component Sim4 complex plays a fundamental role in the assembly of a functional kinetochore. It affects centromere association of the histone H3 variant CENP-A as well as kinetochore association of the DASH complex. Here, multicopy suppressor analysis of a mutant version of the Sim4 complex component Mal2 identified the essential Fta2 kinetochore protein, which is required for bipolar chromosome attachment. Kinetochore localization of Mal2 and Fta2 depends on each other, and overexpression of one protein can rescue the phenotype of the mutant version of the other protein. fta2 mal2 double mutants were inviable, implying that the two proteins have an overlapping function. This close interaction with Fta2 is not shared by other Sim4 complex components, indicating the existence of functional subgroups within this complex. The Sim4 complex seems to be assembled in a hierarchical way, because Fta2 is localized correctly in a sim4 mutant. However, Fta2 kinetochore localization is reduced in a spc7 mutant. Spc7, a suppressor of the EB1 family member Mal3, is part of the conserved Ndc80-MIND-Spc7 kinetochore complex.

Chromosomal Proteins, Non-Histone↗

PubMed2005

Centromeric chromatin makes its mark.

Post-translational modifications of core histones, particularly in the N terminus, seem to define different chromatin states in the genome. For instance, actively transcribed regions of euchromatin have a completely different set of 'marks' compared with silent heterochromatin. Recent analyses surprisingly demonstrate that, in addition to containing the histone H3 variant CENP-A, the centromeric chromatin that underlies the kinetochore bears a distinct combination of histone H3 modifications.

Amino Acid Sequence↗

PubMed2004

Analysis of chromatin in fission yeast.

The use of fission yeast as a model system for studies of chromosome biology has contributed to several key advances in the last few years. The structure of its large complex centromeres and composition of its transcriptionally silent heterochromatin resemble those of metazoa. The application of chromatin immunoprecipitation to fission yeast has been instrumental in these advances and we describe an improved version of this technique in detail. In addition, we describe several other techniques, which are useful in the analysis of chromatin in fission yeast.

Chromatin↗

PubMed2004

The Schizosaccharomyces pombe HIRA-like protein Hip1 is required for the periodic expression of histone genes and contributes to the function of complex centromeres.

HIRA-like (Hir) proteins are evolutionarily conserved and are implicated in the assembly of repressive chromatin. In Saccharomyces cerevisiae, Hir proteins contribute to the function of centromeres. However, S. cerevisiae has point centromeres that are structurally different from the complex centromeres of metazoans. In contrast, Schizosaccharomyces pombe has complex centromeres whose domain structure is conserved with that of human centromeres. Therefore, we examined the functions of the fission yeast Hir proteins Slm9 and the previously uncharacterised protein Hip1. Deletion of hip1(+) resulted in phenotypes that were similar to those described previously for slm9 Delta cells: a cell cycle delay, synthetic lethality with cdc25-22, and poor recovery from nitrogen starvation. However, while it has previously been shown that Slm9 is not required for the periodic expression of histone H2A, we found that loss of Hip1 led to derepression of core histone genes expression outside of S phase. Importantly, we found that deletion of either hip1(+) or slm9(+) resulted in increased rates of chromosome loss, increased sensitivity to spindle damage, and reduced transcriptional silencing in the outer centromeric repeats. Thus, S. pombe Hir proteins contribute to pericentromeric heterochromatin, and our data thus suggest that Hir proteins may be required for the function of metazoan centromeres.

Base Sequence↗

PubMed2003

Chromosome segregation: clamping down on deviant orientations.

Chromosome segregation depends on proper orientation of sister kinetochores. The protein Csm1 is required for mono-orientation of sister kinetochores at meiosis I in budding yeast. Surprisingly, its homologue in fission yeast appears instead of clamp micro-tubule binding sites together on single mitotic kinetochores so that they all face one spindle pole.

Cell Cycle Proteins↗