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Dissertation(Kuo-Fang Shen).pdf (9.63 MB)

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MITOTIC AND NON-MITOTIC ROLES OF THE NIMA KINASE IN ASPERGILLUS NIDULANS

Shen, Kuo-Fang
http://rave.ohiolink.edu/etdc/view?acc_num=osu1366289383

Abstract Details

2013, Doctor of Philosophy, Ohio State University, Molecular, Cellular and Developmental Biology.
The NIMA kinase is required for mitosis and promotes chromosome condensation, the opening of nuclear pore complexes (NPCs) and mitotic spindle functions in Aspergillus nidulans. To define NIMA localization in live cells, we endogenously tagged NIMA with GFP and followed it throughout the cell cycle using 4D spinning disc confocal microscopy. During mitotic entry NIMA first appears at spindle pole bodies (SPBs). After NIMA localizes to SPBs they separate to help form the mitotic spindle and NIMA further spreads around the nuclear envelope locating to NPCs. During telophase and early G1, NIMA localizes back to SPBs and then disperses from SPBs in G1. TINA (two-hybrid interactor of NIMA) locates to SPBs at the G2-M transition after activation of NIMA. To understand the mitotic roles of TINA at the SPBs it was affinity purified. We discovered a novel TINA-binding partner, AN10137, designated as AnWDR8, a conserved WD40 domain containing protein, by mass spectrometry. The distributions of AnWDR8 and TINA are identical. Deletion analysis revealed that TINA is required for the localization of AnWDR8 to nuclei and SPBs and that AnWDR8 is crucial for TINA protein levels. TINA is also required for the location of NIMA back to SPBs during mitotic exit. Thus NIMA is first required for the SPB location of TINA and TINA is in turn required for the SPB location of NIMA. In addition to a negative role of TINA in regulating the formation of astral microtubules, we found TINA is also required for anchoring spindle microtubules to SPBs during mitosis. This role of TINA in anchoring spindle microtubule to SPBs is consistent with that of Msd1, a fission yeast TINA homolog. In addition to the mitotic localization of NIMA in the nucleus, we found that NIMA locates to cell tips, forming septa and mature septa in interphase. NIMA locates to septum formation sites as a transient ring as septa are formed and it stays at the fully formed septa as a central disc structure near the septal pore. NIMA is a dynamic protein at mature septa where it stays in interphase and is removed during mitosis. The dynamic NIMA distributions at mature septa lead us to hypothesize that NIMA plays a role in regulating opening and closing of septal pores. We showed septal pores are open in interphase and closed during mitosis. Given that NIMA stays at mature septa in interphase and is removed from mature septa during mitosis and septal pores are open in interphase and closed during mitosis, these data suggest that NIMA promotes the opening of septal pores in interphase. During mitosis, NIMA is removed from mature septa to cause the closing of septal pores and then goes to NPCs to trigger the opening of nuclear pores. In conclusion, the highly dynamic localizations of NIMA suggest it regulates several mitotic processes, including SPB functions in coordination with TINA and AnWDR8, partial disassembly of NPCs, formation of septa and the closing and opening of mature septal pores.
Stephen Osmani (Committee Member)
Anita Hopper (Committee Member)
Harold Fisk (Committee Member)
Jian-Qiu Wu (Committee Member)
198 p.
Cellular Biology

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Citations

  • Shen, K.-F. (2013). MITOTIC AND NON-MITOTIC ROLES OF THE NIMA KINASE IN ASPERGILLUS NIDULANS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366289383

    APA Style (7th edition)

  • Shen, Kuo-Fang. MITOTIC AND NON-MITOTIC ROLES OF THE NIMA KINASE IN ASPERGILLUS NIDULANS . 2013. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1366289383.

    MLA Style (8th edition)

  • Shen, Kuo-Fang. "MITOTIC AND NON-MITOTIC ROLES OF THE NIMA KINASE IN ASPERGILLUS NIDULANS ." Doctoral dissertation, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366289383

    Chicago Manual of Style (17th edition)

osu1366289383
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This open access ETD is published by The Ohio State University and OhioLINK.