Biomedical Engineering Reference
In-Depth Information
Wild type
Mutants of PCP genes
A
vang-1
PVQ
?
B
Follower
PVP
PVQ
Pioneer
Pioneer
Left
AVG
Follower
fmi-1
PVQ
PVP
Pioneer
Follower
AVG
Pioneer
Right
PVP
Pioneer
Pioneer
AVG
C
vang-1
Left
Left
dsh-1
Vulva
Vulva
VC4
VC4
VC5
VC5
Right
prkl-1
Right
Figure 3.7 Functions of core PCP components in C. elegans. (A) Intestinal lumen that is
normally surrounded by two cells is instead surrounded by three cells in vang-1 mu-
tants. (B) Pioneer and follower axons of PVP and PVQ neurons, respectively, that are nor-
mally on the left side crossed the ventral midline and joined the right axon track. (C) VC4
and VC5 neurons that are normally bipolar have extra neurites in vang-1, dsh-1,orprkl-1
mutants.
Dishevelled, suggesting that VANG-1 functions in a PCP-like pathway in
intestinal morphogenesis.
The core PCP components are also involved in the formation of axons or
neurites of some neurons.
fmi-1
functions in the navigation of pioneer axons
and axons that follow preexisting axons with distinct genetic interaction
with
lin-17
/Fzd (
Steimel et al., 2010
)(
Fig. 3.7
B). Although
lin-17
/Fzd mu-
tants similarly affect both the pioneer and the follower axons,
lin-17
en-
hances
fmi-1
phenotype in the pioneer axons, while it does not in the
follower axons, suggesting that
lin-17
acts in parallel to
fmi-1
in the pioneer
axons, while they act together in the follower axons. Intracellular domain of
FMI-1 is essential for the guidance of pioneer axon but dispensable for that
of follower axons. It was proposed that FMI-1 functions as a receptor or a
