microbiology

Questions

1) Cite the two basic embryological processes for cell determination and explain the main difference between them.

2) The experiment below, using sea urchin embryos, illustrate both processes for cell determination. Identify which one is represented by each part of the experiment (A and B) and explain your decision briefly.

A Abnormal ~ normal development development normal normal development development

B

Paper-based

1) In all the figures where electroporation of DNA in chicken embryos is performed, the authors show a panel with GFP. Why is GFP electroporated in these cells, together with the experimental gene (Snail or Sox)? What kind of control and information does the GFP signal provide? You may want to read about electroporation. (https://en.wikipedia.org/wiki/Electroporation)

2) Based on information in Figure 1E add the appropriate arrow ( or ) between Snail and RhoB as you would find in a GRN. Justify your choice briefly by describing precisely the result presented in 1E

Snail RhoB

3) If you were to analyze the promoter sequence of the RhoB gene, what would you expect to find? Explain briefly

· Sequences for snail to bind as an activator

· Sequences for snail to bind as a repressor

· No binding sequences for Snail

4) The figure to the right is parts 1F and 1G of the paper, together with a schematic dorsal view of an early chicken gastrula. The dotted white lines in F and G represent the position of the primitive streak.

Indicate on the schematic where the electroporation was done.

5) Which cellular structure contains laminin? How is the absence of laminin on the electroporated side consistent with the function of snail in EMT? For this question, you want to also review the steps involved in the epithelial to mesenchymal transition (PowerPoint on OAKS).

6) This is part of Figure 3.

a)Describe panels B and N, as well as P and Q in your own word, explaining in particular the effect on Sox3 expression.

b) Predict the expected data for laminin expression. Would it be up or down in the electroporated area compared to normal? Justify your answer.

7) Explain what are gene markers

8) Based on the data presented in Figure 6A,B, and F fill, the GRN below with the correct arrows (. or ). Justify each placed arrow briefly by describing the appropriate part of the figure