Biology Reference
In-Depth Information
Fig. 6.1 Centrosome duplication cycle: the intrinsic centrosome asymmetry. Prior to
centrosome duplication, a cell has a single centrosome (named mother centrosome) containing
one ''older'' centriole (i.e., the mother centriole) and one ''newer'' centriole (i.e., the daughter
centriole). The mother centriole (black) has distal and subdistal appendages (black branches),
while the daughter centriole (red) does not. Preparing for centrosome duplication, two centrioles
disengage from each other and then each centriole begins duplicating with new centrioles (gray
and purple) nucleating by their sides. At a certain time point, the two pairs of centrioles separate
from each other, forming two centrosomes. The mother centrosome contains the original mother
centriole (black), and the daughter centrosome contains the original daughter centriole (red). The
daughter centrosome is in her unmatured state at this time point, and will take time (e.g., by the
end of current cell cycle or even next cell cycle) to become fully matured. After cell division, the
mother centrosome is inherited by one daughter cell. In the other daughter cell, the original
daughter centriole in the daughter centrosome matures as the ''new'' mother centriole with
developed appendages (red branches), and the matured daughter centrosome can be denoted as
the mother centrosome upon entry into the next cell cycle
the mother centrosome typically organizes a greater amount of Cnn than the daughter
centrosome, since mother centrosomes are more mature and begin incorporating Cnn
earlier. Furthermore, centrosomes behave asymmetrically during abscission, the last
stage of cytokinesis (Gromley et al.
2005
; Kuo et al.
2011
). It has been shown that in
Hela cells the mother centriole moves very close to the midbody right before abscission
(Piel et al.
2001
), and secretory vesicles carrying components required for abscission
move to the site of abscission from the cell containing the daughter centrosome,
