A hypothesis of nucleosome evolution considering mutational analysis.

Nucleosomes are complexes of DNA and histone proteins that form the basis of eukaryotic chromatin. Eukaryotic histones are descended from Archaean homologs; however, how this occurred remains unclear. Our previous genetic analysis on the budding yeast nucleosome identified 26 histone residues conserved between S.

Physiologically based pharmacokinetic model analysis of the inhibitory effect of vonoprazan on the metabolic activation of proguanil.

We previously reported that repeated oral administration of vonoprazan (VPZ) followed by oral administration of proguanil (PG) in healthy adults increased blood concentration of PG and decreased blood concentration of its metabolite cycloguanil (CG) compared with administration of PG alone. In this study, we investigated whether this interaction can be quantitatively explained by VPZ inhibition of PG metabolism. In an in vitro study using human liver microsomes, VPZ inhibited CG formation from PG in a concentration-dependent manner, and the inhibition was enhanced depending on preincubation time.

Functional Analyses of an Evolutionarily Conserved Acidic Patch on the Nucleosome.

The eukaryotic canonical nucleosome has an acidic patch on each H2A/H2B dimer. This acidic patch is also detected in histone variants, such as the H2A.Z (yeast Htz1)/H2B dimer.

Transcription destabilizes centromere function.

Bi-oriented attachment of microtubules to the centromere is a pre-requisite for faithful chromosome segregation during mitosis. Budding yeast have point centromeres containing the cis-element proteins CDE-I, -II, and -III, which interact with trans-acting factors such as Cbf1, Cse4, and Ndc10. Our previous genetic screens, using a comprehensive library of histone point mutants, revealed that the TBS-I, -II, and -III regions of nucleosomes are required for faithful chromosome segregation.

Analysis of the molecular evolution of histone variant H2A.Z using a linker-mediated complex strategy and yeast genetic complementation.

The histone variant H2A.Z is deposited into chromatin by specific machinery and is required for genome functions. Using a linker-mediated complex strategy combined with yeast genetic complementation, we demonstrate evolutionary conservation of H2A.

An improved functional analysis of linker-mediated complex (iFALC) strategy.

The functional analysis of linker-mediated complex (FALC) strategy that facilitates functional analysis of a common subunit of multi-subunit protein complexes in cells constitutes three steps; (1) a common subunit is fused to a specific subunit via recombinant DNA, (2) mutation is introduced into a portion of the common subunit of the fused protein, and (3) the mutational effect on the fused protein is evaluated by transformation and analysis of multiple appropriate gene knockout yeast strains. Conceptually, the FALC strategy is applicable to any common subunit of multi-subunit protein complexes in any cell type. However, the proximity of two subunits to fuse, preparation of multiple gene knockout cells, and utilization of yeast cells can together prevent the practical and broad usage of the FALC strategy for analyzing all multi-subunit complexes in all cell types.

Roles of common subunits within distinct multisubunit complexes.

Currently, there is no method to distinguish between the roles of a subunit in one multisubunit protein complex from its roles in other complexes in vivo. This is because a mutation in a common subunit will affect all complexes containing that subunit. Here, we describe a unique method to discriminate between the functions of a common subunit in different multisubunit protein complexes.

Nucleosome surface containing nucleosomal DNA entry/exit site regulates H3-K36me3 via association with RNA polymerase II and Set2.

A nucleosome is composed of intrinsically disordered histone tails and a structured nucleosome core surrounded by DNA. A variety of modifiable residues on the intrinsically disordered histone tails have been identified in the last decade. Mapping of the functional residues on the structured nucleosome core surface was recently initiated by global analysis of a comprehensive histone point mutant library (histone-GLibrary).

Global analysis of core histones reveals nucleosomal surfaces required for chromosome bi-orientation.

The attachment of sister kinetochores to microtubules from opposite spindle poles is essential for faithful chromosome segregation. Kinetochore assembly requires centromere-specific nucleosomes containing the histone H3 variant CenH3. However, the functional roles of the canonical histones (H2A, H2B, H3, and H4) in chromosome segregation remain elusive.