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doctoral thesis
The role of bridging microtubules in anaphase of cell division
Zagreb: University of Zagreb, Faculty of Science, 2020. urn:nbn:hr:217:983703
Buđa, Renata
University of Zagreb
Faculty of Science
Department of Biology

Cite this document

Buđa, R. (2020). The role of bridging microtubules in anaphase of cell division (Doctoral thesis). Zagreb: University of Zagreb, Faculty of Science. Retrieved from https://urn.nsk.hr/urn:nbn:hr:217:983703

Buđa, Renata. "The role of bridging microtubules in anaphase of cell division." Doctoral thesis, University of Zagreb, Faculty of Science, 2020. https://urn.nsk.hr/urn:nbn:hr:217:983703

Buđa, Renata. "The role of bridging microtubules in anaphase of cell division." Doctoral thesis, University of Zagreb, Faculty of Science, 2020. https://urn.nsk.hr/urn:nbn:hr:217:983703

Buđa, R. (2020). 'The role of bridging microtubules in anaphase of cell division', Doctoral thesis, University of Zagreb, Faculty of Science, accessed 13 January 2025, https://urn.nsk.hr/urn:nbn:hr:217:983703

Buđa R. The role of bridging microtubules in anaphase of cell division [Doctoral thesis]. Zagreb: University of Zagreb, Faculty of Science; 2020 [cited 2025 January 13] Available at: https://urn.nsk.hr/urn:nbn:hr:217:983703

R. Buđa, "The role of bridging microtubules in anaphase of cell division", Doctoral thesis, University of Zagreb, Faculty of Science, Zagreb, 2020. Available at: https://urn.nsk.hr/urn:nbn:hr:217:983703

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Metadata
TitleThe role of bridging microtubules in anaphase of cell division
Title (croatian)Uloga premošćujućih mikrotubula u anafazi stanične diobe
AuthorRenata Buđa
MentorIva Marija Tolić (mentor)
Committee memberJuraj Simunić (predsjednik povjerenstva)
Committee memberDubravko Pavoković (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Science
(Department of Biology)
Zagreb
Defense date and country2020-05-13, Croatia
Scientific / art field,
discipline and subdiscipline		NATURAL SCIENCES
Biology
Universal decimal classification
(UDC)		577 - Biochemistry. Molecular biology. Biophysics
Abstract
During cell division, microtubules of the mitotic spindle segregate chromosomes by exerting forces on kinetochores, protein complexes on the chromosomes. The central question is which forces drive chromosome segregation. The current model for anaphase in human cells includes shortening of kinetochore fibers and separation of spindle poles, processes that require kinetochore-pole connections. By combining laser ablation, photoactivation and protein depletion, we show that kinetochores can separate without the attachment to the pole. This separation requires the bridging fiber, which connects sister k-fibers whereby astral microtubules do not contribute to the separation. Bridging microtubules in intact spindles slide apart together with k-fibers, indicating strong crosslinks between them. Kinetochore segregation and pole separation is slower after depletion of MKLP1/KIF23 (kinesin-6), faster after depletion of KIF4a (kinesin-4), and unaffected by reduction of Eg5/KIF11 (kinesin-5) or KIF15/Hklp2 (kinesin-12). We assume that motor-generated sliding in the bridging fibers drives pole separation and pushes k-fibers poleward, thereby working together with k-fiber shortening to segregate chromosomes.
Abstract (english)
Tijekom stanične diobe, mikrotubuli u diobenom vretenu razdvajaju kromosome stvarajući sile na kinetohore, proteinske komplekse na kromosomima. Unatoč mnogim istraživanjima u ovom području, ostalo je upitno koje sile upravljaju segregacijom kromosoma. Trenutno prihvaćen model za anafazu u ljudskim stanicama obuhvaća skraćivanje kinetohornih mikrotubula i razdvajanje polova diobenog vretena, procese koji zahtijevaju vezu između kinetohore i pola. Primjenom laserske ablacije, fotoaktivacije i deplecije proteina, u ovom radu je pokazano da se kinetohore mogu razdvajati i kada nema veze sa polom diobenog vretena. Takvo razdvajanje zahtjeva antiparalelna premošćujuća vlakna, koja povezuju sestrinska kinetohorna vlakna i kližu jedan preko drugog, dok astralni mikrotubuli ne doprinose navedenom procesu razdvajanja. Također, premošćujuća vlakna u netaknutom diobenom vretenu kližu zajedno sa kinetohornim vlaknima, a to upućuje na snažnu povezanost između te dvije populacije vlakana. Brzine razdvajanje kinetohora i polova su manje nakon utišavanja MKLP1/KIF23 (kinezin-6), više nakon utišavanja KIF4a (kinezin-4) i nepromijenjene nakon inhibicije/utišavanja Eg5/KIF11 (kinezin-5) i/ili KIF15/Hklp2 (kinezin-12) proteina. Zaključak ovog rada je da premošćujući mikrotubuli kližu, vjerojatno uz pomoć motornih proteina, odgurujući tako kinetohorna vlakna sa kinetohorama, kao i polove, jedne od drugih. Takav mehanizam djeluje skupa sa skraćivanjem kinetohornih vlakana i posljedica njihovog zajedničkog djelovanja je razdvajanje kromosoma u ljudskim stanicama.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:217:983703
Promotion2020
Study programmeTitle: Biology
Study programme type: university
Study level: postgraduate
Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija (doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija)
Type of resourceText
File originBorn digital
Access conditionsOpen access
Terms of useLicence In copyright icon
RepositoryRepository of the Faculty of Science
Created on2020-07-23 11:58:08

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