Schlienger S, Yam PT, Balekoglu N, Ducuing H, Michaud JF, Makihara S, Kramer DK, Chen B,

Fasano A, Berardelli A, Hamdan FF. Genetics of mirror movements identifies a multifunctional

complex required for Netrin-1 guidance and lateralization of motor control. Science Advances. 2023

May 12;9(19):eadd5501.

QUESTION 1

Read the above paper by Schlienger et al. (2023). In this paper the authors investigate a RhoGEF called Arhgef7. How is the function of this Gef different or like ephexin which is active in RhoA-dependent chemoinhibition? In your answer discuss the model proposed for the action of Arhgef7 in axon guidance and detail the molecular pathways and their intracellular effects downstream of Rac1 that modulate Netrin-1 mediated axon growth (you must refer to relevant literature to support your answer and hand draw diagram(s) to help explain your answer).

QUESTION 2

Fig. 2D inSchliengeret al. (2023) presents data for a growth cone guidance assay. First, briefly describe the Dunn chamber axon turning assay (include relevant reference/s and hand drawn figure). Fig 2E is a different way of presenting the data used in Fig. 2D. What does this scatter plot data reveal about the behaviour of the growth cones that is not discussed by the authors and why is this important for the correct interpretation of results. Ensure you provide reference(s) to support your conclusion.