Reference no: EM132565466

Lola, a 2-year-old female, is assessed by her family GP after her Mother became concerned that she was not growing as much as other children around the same age. Physical examination of Lola shows she has a temperature of 37.2°C and a prominent liver. Her height is below average for her age, as is her weight.

After initial blood test and urinalysis, Lola's doctor identifies that Lola is hypoglycaemic, with increased blood lipids and ketone bodies. Lola undergoes an oral glucose tolerance test to determine the cause of his hypoglycaemia. Her blood glucose increases to 5 mM upon a single dose of glucose via nasogastric tube but decreases to 0.8 mM within 6 hours.

Lola's doctor rules out diabetes and conducts subsequent tests for a glycogen storage disorder.

Question 1: Based on Lola's symptoms, her doctor rules out a deficiency in glycogen synthase. Why is this possible?

Question 2: Lola's doctor identifies a deficiency of glycogen phosphorylase. Describe the role of this enzyme in relation to glycogen metabolism, and how this compares to Lola's glycogen metabolism, in line with her symptoms.

Question 3: Genetic screening revealed Lola carries a mutation in the gene for Glycogen Phosphorylase. Which of the following mutations is Lola most likely to have and why?

-An amino acid deletion at the residue phosphorylated by phosphorylase kinase or,

-A mutation rendering the allosteric regulatory site unable to bind glucose

In the fly (Drosophila), a gene called pax6 is required for proper eye development. It encodes a transcription factor protein.

Question 1: You decide to conduct Pax6 immunofluorescence on tissue sections of mouse embryos. What key reagent do you need to carry out this method?

Question 2: Your immunofluorescence experiment shows that Pax6 is expressed in the embryonic brain and eyes.

a. What method you would use to show that Pax6 gene is required for eye development in the mouse?

b. In three dot points, outline how this method is carried out.

Question 3: You find that Pax6 expression in embryonic mouse eyes is strongly induced by TGF-β signaling. In three dot points, describe how the TGF-β pathway would work to activate the Pax6 gene.

Question 4: You find that Pax6 can regulate a population of stem cells in the developing eye. Name TWO characteristics of stem cells