Cell Division

1. Mitosis 1) Dephosphorylated M/Cdk drive entry into mitosis 2) Condensin helps configure duplicated chromosome for separation condensin

3) Mitotic spindle (1) Microtubule-based machine 3 classes of M.T. of the mitotic spindle in an animal cells

(2) Centrosome duplication occurs early in the cell cycle

(3) M.T.-dependent motor protein govern spindle assembly and function

(4) How the cell regulate the appropriate spindle length?

(5) M.T. instability increase greatly in mitosis

Spindle self-organization by motor proteins 4) Mitotic chromosome promote bipolar spindle assembly Spindle self-organization by motor proteins

Bipolar spindle assembly w/o centrosome

5) Kinetochore attach sister chromatids to the spindle M.T. attachment site in a kinetochore

Capture of centrosome M.T. by kinetochores

6) Multiple forces move chromosomes on the spindle (1) How Depolymerization may pull the kinetochore toward the spindle pole

(2) M.T. flux in the metaphase spindle

(3) How opposing force may drive chromosomes to the metaphase plate

7) Chromosomes segregation in Anaphase A and B

2. Cytokinesis

1) Actin & myosin II in the contractile ring generate the force for cytokinesis

Midbody

2) RhoA* triggers assembly and contraction of the contractile ring

3) M.T. of the mitotic spindle determine the plane of animal cell division 3 current models of how the M.T. of the anaphase spindle generate signals that influence the positioning of the contractile ring

Experimental evidence

4) Phragmoplast guides cytokinesis in higher plants Cytokinesis in a higher plant cell

5) Membrane-enclosed organelles must be distributed to daughter cells during cytokinesis 6) However, some cells reposition their spindle to divide asymmetrically

7) Mitosis can occur w/o cytokinesis Early stage of development of Drosophila embryo