Fig. 3.

Needle-induced fusion of two nucleoli. (A) Image showing a microneedle that has been used to move two nucleoli together. (B) Time course of the distance between the two nucleoli. Initially they are not touching. At approximately 75 s, they are brought into contact with one another, but they do not appear to begin fusing until approximately 500 s, when they fuse into a single round sphere on a timescale of τ ∼ 350 s. (C) Images showing the sequence of events. The needle is visible in the second frame (needle tip position denoted by the asterisk).