Maternal Effects
P0
F1
Phenotype
F2
Phenotype
m/+ x m/+
Rare case
m/+ x m/+
m/m
m/m
mutant
wild-type
m/m
m/m
mutant
mutant
A maternal effect is the phenomena where the genotype of a mother is
expressed in the phenotype of its offspring, unaltered by paternal
genetic influence
ABp
ABa
P2
EMS
Immediately after
cell division
ABp
ABa
Some time after
cell division
P2
ABp
ABp
EMS
ABa
ABa
P2
EMS
P2
P2
EMS
Gut
No Gut
Gut
Five genes (mom-1, 2, 3, 4, 5) have been identified to be
important for gut differentiation
ABp
ABa
P2
mom-2
EMSmom-5
MOM-1: Drosophila PORCUPINE
MOM-2: Wnt homologue
MOM-3: Drosophila and human Wntless
MOM-4: MAP kinase kinase kinase homologue
MOM-5: Frizzled homologue
WNT signaling
MOM-2
MOM-5
POP-1
WNT Biogenesis
MOM-2
MOM-1
MOM-3
How did the author verify that mom
mutants produce more mesoderm?
A. By dye staining
B. By immunostaining using an antibody specific for
pharyngeal muscle cell
C. By polarized light
D. By isolation and reconstitution experiments
E. None of the above
How did the authors find out where mom-2 is
acting to affect EMS cell fate determination?
A. By examining the cell lineage
B. By antibody staining
C. By genetic analysis
D. By isolation and reconstitution of blastomeres
E. None of the above
How did the authors know that mom-2
encodes a WNT homologue
A. By transformation rescue
B. By antisense RNA phenocopy
C. By sequencing analysis and identifying mom2 mutations in the WNT homologue
D. All of the above
E. None of the above
What is Wnt signaling?
A. It is a receptor important for cell-cell interaction
B. It is a secreted protein important for cell-cell
interaction
C. It refers to both the receptor and the signal and
the upstream and downstream components
D. It has nothing to do with cell-cell signaling
What did you learn most from this paper?
A. What is the receptor in EMS that receives the signal from P2?
B. What is the ligand that signals from P2 to EMS
C. Wnt signaling can change orientation of mitotic spindle
D. Genetic analysis is very powerful in identifying signaling
components of a biological process
E. Isolation and reconstitution of blastomeres is a
powerful method to understand embryo development.