10. A mouse model is created in which the Noggin protein is knocked out. How wou
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Question
10. A mouse model is created in which the Noggin protein is knocked out. How would this affect development in the mouse?
a. Neuroectoderm would differentiate into epidermis instead of neural tissue.
b. Somites would differentiate into neural tissue instead of muscle and bone.
c. Target gene expression in the notochord would be decreased.
d. Fibroblast growth factor would have no effect on developing cells.
e. Wnt would be unable to bind to the Frizzled protein.
11. A pregnant experimental animal was treated with excess vitamin A. Which outcome would you expect to see in her offspring?
a. Increased number of cells present in laminar layer 6
b. Disruption in transcriptional regulation of other inductive signals like Sonic hedgehog
c. Persistence of notochord after birth
d. Development of the floorplate and roofplate in abnormal locations in the neural tube
12. A young patient is brought to the doctor because of failure to thrive and is diagnosed with lissencephaly. Which test results might have led to this diagnosis?
a. A genetic analysis showing a mutation in the Smoothened gene
b. A visual analysis revealing lack of closure of the posterior neural tube
c. An MRI revealing a tumor in the cerebellum
d. An abdominal X-ray showing an obstructed colon
e. An MRI revealing a lack of sulci and gyri in the cerebral cortex
Explanation / Answer
Nogin is a protein which plays an imporatant role in the development of nerve tissue, bones and muscles. Amino acid sequence of Noggin found in human body is quite similar to that found in the mouse. Noggin is released from notochord and helps in formation of dorsal structure of the body. different experiments are conducted on mice which shows that it not only helps in the formation of bones but also in learning and neural tube fusion.
Mouse knockout model check that absence of noggin affect the embryological devlopment.
It shows malformation in through notochord and neural axis which causes disorientation in body axis. Moreover it also shows hearing loss which is caused by ectopic bone bridge.
Ans 11: If an pregnant experimental animal is treated with vitamin A then it causes birth defects which affect the tissue derived from cranial neural crest.
Ans 12: Lissencephaly is a desease which is caused by neural migration defect. It is characterised by thickened cerebral corteex with three or four abnormal layer. It is an abnormality in the cortical devlopment which produced thckened cortical grey matter.
It is diagonised MRI
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