Photoactivation of Hsap\RAC1^{PA.Q61L.Scer\UAS.T:Disc\RFP-mCherry,T:Zzzz\PT1} in the centre of a single border cell (where its expression is under the control of Scer\GAL4^slbo.2.6) has negligible effect on border cell cluster migration if the photoactivated cell is at the front of the border cell cluster. However, if the photoactivated cell is at the back of the border cell cluster, net cluster movement backwards is seen.

In the absence of illumination migration of border cells expressing Hsap\RAC1^{PA.Q61L.Scer\UAS.T:Disc\RFP-mCherry,T:Zzzz\PT1} under the control of Scer\GAL4^slbo.2.6 is unperturbed.

Photoactivation of Hsap\RAC1^{PA.Q61L.Scer\UAS.T:Disc\RFP-mCherry,T:Zzzz\PT1} at the rear of border cell clusters expressing Hsap\RAC1^{PA.Q61L.Scer\UAS.T:Disc\RFP-mCherry,T:Zzzz\PT1} under the control of Scer\GAL4^slbo.2.6 results in reverse border cell migration. When photoactivation is stopped, border cells stall for a variable period of time before regaining forward migration.

Photoactivation of Hsap\RAC1^{PA.Q61L.Scer\UAS.T:Disc\RFP-mCherry,T:Zzzz\PT1} in border cell clusters expressing Hsap\RAC1^{PA.Q61L.Scer\UAS.T:Disc\RFP-mCherry,T:Zzzz\PT1} under the control of Scer\GAL4^slbo.2.6 can redirect border cell migration. Either forward or backward movement can be promoted, depending on the site of photoactivation, although the average speed of forward migration exceeds that of backward migration by 4.5 fold. Photoactivation can redirect border cells within the anterior third of the egg chamber, while in the middle third, photoactivation has little effect. In the posterior third of the egg chamber, photoactivation can drive border cells towards the side of the chamber, in between nurse cells. Photoactivation of Hsap\RAC1^{PA.Q61L.Scer\UAS.T:Disc\RFP-mCherry,T:Zzzz\PT1} in one cell of a border cell cluster results in retraction of protrusions by the other cells and movement of the cluster in the direction of the light (this occurs whether the illumination is at the front or back of the cluster).