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Mitsuhiro Yanagida

Publications and source records attributed to Mitsuhiro Yanagida.

40 records · Page 3Linked to original sources

Polo boxes and Cut23 (Apc8) mediate an interaction between polo kinase and the anaphase-promoting complex for fission yeast mitosis.

The fission yeast plo1(+) gene encodes a polo-like kinase, a member of a conserved family of kinases which play multiple roles during the cell cycle. We show that Plo1 kinase physically interacts with the anaphase-promoting complex (APC)/cyclosome through the noncatalytic domain of Plo1 and the tetratricopeptide repeat domain of the subunit, Cut23. A new cut23 mutation, which specifically disrupts the interaction with Plo1, results in a metaphase arrest. This arrest can be rescued by high expression of Plo1 kinase. We suggest that this physical interaction is crucial for mitotic progression by targeting polo kinase activity toward the APC.

Alleles↗

Cut1/separase C-terminus affects spindle pole body positioning in interphase of fission yeast: pointed nuclear formation.

BACKGROUND: The separase-securin complex is required for anaphase. Separase activated by securin destruction cleaves the cohesin subunit Scc1/Rad21 enriched in kinetochores. Fission yeast Cut1/separase resides in interphase cytoplasm and mobilizes to the spindle and the spindle pole bodies (SPBs) in mitosis, while Cut2/securin remains in the nucleus from interphase to metaphase, and temporarily locates at the short spindle. RESULTS: We here report a novel SPB-led dynamic nuclear movement in fission yeast, when the Cut1 C-terminal fragment is over-expressed. The tip of the pointed nucleus contained both SPB and centromeric DNA, and rapidly moved along the bundled cytoplasmic microtubules. The same pointed nucleus was produced when the human separase C-fragment was over-expressed. The pointed nuclear formation did not require the protease site of separase, but required the conserved C-terminus and a microtubule- and kinetochore-binding protein Mtc1/Alp14, a homologue of frog XMAP215 and budding yeast Stu2. The movement-inducing C-fragment should be cytoplasmic, as the pointed nucleus was abolished when the fragment contained the NLS (nuclear localization signal). CONCLUSIONS: Overproduced separase C-fragment abolishes correct SPB-positioning in interphase. Resulting pointed nuclear formation (alternatively called 'pigtail movement') requires cytoplasmic microtubules and Mtc1/Alp14.

Catalytic Domain↗

Does a GATA factor make the bed for centromeric nucleosomes?

CENP-A is an evolutionarily conserved, centromere-specific histone H3 variant. It remains a great mystery how CENP-A is correctly incorporated into the centromere, a restricted chromosomal region, despite the presence of an overwhelming amount of histone H3. We identified a cell cycle-regulated GATA factor, Ams2, as a component of the CENP-A localization pathway in fission yeast. Unexpectedly, this putative transcription factor, which belongs to a protein family containing members that remodel nucleosomes, appeared to bind to and function at the central region of the centromere. Although the centromere has in general been considered transcriptionally inactive, fission yeast's outer centromeric region has recently been shown to encode non-translated snRNAs that are involved in heterochromatin formation. Transcription factors such as Ams2 may directly transcribe some unidentified non-translated centromeric RNAs. Transcription and/or remodeling of the nucleosomes at the centromeres may be important for the precise incorporation of CENP-A in fission yeast.

Autoantigens↗