Chihiro Horigome

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Chromatin mobility is thought to facilitate homology search during homologous recombination and to shift damage either towards or away from specialized repair compartments. However, unconstrained mobility of double-strand breaks could also promote deleterious chromosomal translocations. Here we use live time-lapse fluorescence microscopy to track the(More)
Persistent DNA double-strand breaks (DSBs) are recruited to the nuclear periphery in budding yeast. Both the Nup84 pore subcomplex and Mps3, an inner nuclear membrane (INM) SUN domain protein, have been implicated in DSB binding. It was unclear what, if anything, distinguishes the two potential sites of repair. Here, we characterize and distinguish the two(More)
High-resolution imaging shows that persistent DNA damage in budding yeast localizes in distinct perinuclear foci for repair. The signals that trigger DNA double-strand break (DSB) relocation or determine their destination are unknown. We show here that DSB relocation to the nuclear envelope depends on SUMOylation mediated by the E3 ligases Siz2 and Mms21.(More)
Two interacting ribosome biogenesis factors, Ebp2 and Rrs1, associate with Mps3, an essential inner nuclear membrane protein. Both are found in foci along the nuclear periphery, like Mps3, as well as in the nucleolus. Temperature-sensitive ebp2 and rrs1 mutations that compromise ribosome biogenesis displace the mutant proteins from the nuclear rim and lead(More)
Rrs1 has an essential role in 60S ribosomal subunit assembly in Saccharomyces cerevisiae. We isolated a temperature-sensitive kcs1 mutant that suppresses the cold sensitivity of rrs1-1. The kcs1 allele, resulting in truncation of inositol 6 phosphate kinase domain, and kcs1 disruption suppress a defect of rrs1-1 in 60S ribosomal subunit assembly. These(More)
The nucleolus, the most prominent structure observed in the nucleus, is often called a “ribosome factory.” Cells spend an enormous fraction of their resources to achieve the mass-production of ribosomes required by rapid growth. On the other hand, ribosome biogenesis is also tightly controlled, and must be coordinated with other cellular processes.(More)
Ebp2p, the yeast homolog of human Epstein-Barr virus nuclear antigen 1-binding protein 2, is essential for biogenesis of the 60 S ribosomal subunit. Two-hybrid screening exhibited that, in addition to factors necessary for assembly of the 60 S subunit, Ebp2p interacts with Rps16p, ribosomal protein S16, and the 40 S ribosomal subunit assembly factor,(More)
Rrs1p is a ribosomal protein L11-binding protein in Saccharomyces cerevisiae. We have obtained temperature-sensitive rrs1 mutants by random PCR mutagenesis. [(3)H]Methionine pulse-chase analysis reveals that the rrs1 mutations cause a defect in maturation of 25S rRNA. Ribosomal protein L25-enhanced green fluorescent protein, a reporter of the 60S ribosomal(More)
Rrs1p, a ribosomal protein L11-binding protein, has an essential role in biogenesis of 60S ribosomal subunits. We obtained conditionally synthetic lethal allele with the rrs1-5 mutation and determined that the mutation is in REX1, which encodes an exonuclease. The highly conserved leucine at 305 was substituted with tryptophan in rex1-1. The rex1-1 allele(More)
We have found that Ebp2p is essential for maturation of 25S rRNA and assembly of 60S pre-ribosomal subunits in Saccharomyces cerevisiae. We obtained three temperature-sensitive ebp2 mutants by PCR. Polysome analysis revealed that the synthesis of 60S ribosomal subunits was compromised in each of the ebp2 mutants at the restrictive temperature. The ebp2(More)