목차

ABSTRACT ⅰ
TABLE OF CONTENTS ⅲ
LIST OF FIGURES ⅵ
Ⅰ. INTRODUCTION 1
A.Mitochondrial biogenesis and dynamics 1
B.Cellular roles of mitochondrial fission and fusion 5
C.Mitochondria and cell cycle 6
D.Regulation of G2/M transition 8
E.Purpose of the study 9
Ⅱ. MATERIALS AND METHODS 11
A.Reagent and antibodies 11
B.Cell culture and synchronization 11
C.Plasmids, RNAi by shRNA, and transfection 12
D.Flow cytometry for analysis of DNA contents and mitotic index counting 13
E.Time lapse microscopy 13
F.Cyclin B1-associated Cdk1 kinase activity assay 14
G.Detection of BrdU incorporation 15
H.Immunofluorescence staining and confocal microscopy 15
I.Cell proliferation assay 16
J.Senescence-associated β-galactosidase (SA-β-gal) assay 17
K.Analysis of cellular granularity, mitochondrial transmembrane potential, and intracellular ROS levels by flow cytometry 17
L.RNA isolation and reverse transcription-PCR 18
M.Immunoblotting 19
N.Statistical analyses 19
Ⅲ. RESULTS 20
A.Cell cycle-dependent alteration of mitochondrial morphology 20
B.Mitochondrial fragmentation occurs at G2 phase 23
C.Cells with highly elongated mitochondria fail to enter mitosis 26
D.Opa1 knockdown restores the impaired mitotic entry in hFis1-depleted cells 36
E.Overexpression of FoxM1 and Plk1 in hFis1 depleted cells restores the impaired mitotic entry 41
F.Prolonged mitochondrial elongation in hFis1-depleted cells induces senescence-associated phenotypic changes 46
G.Reconstitution of hFis1 to the hFis1-depleted cells reduces positive SA-β-Gal staining 51
H.Opa1 knockdown restores the senescence-associated phenotypic changes in hFis1-depleted cells 55
I.The hFis1 depletion leads to changes in mitochondrial membrane potential and ROS production, and induces DNA damage 61
Ⅳ. DISCUSSION 65
Ⅴ. CONCLUSION 70
Ⅵ. REFERENCES 71
Ⅶ. 국문요약 82