Figure 1. Correlation Between Transcriptional Activation and Hydrogel Binding of Native and Mutated Derivatives of the LC Domain of FUS.
(A) The LC domain of FUS was linked to the DNA binding domain of GAL4 and assayed for activation of a GAL4 reporter gene in transiently transfected U20S cells. Activity of the native LC sequence was compared with 43 variants wherein different number of tyrosine residues were randomly mutated to serine (see text). Identities of specific tyrosine-to-serine changes in each mutant are shown in Table S1. Expression levels for all test protein were assayed by western blotting as shown below histograms. (B) The GFP-linked LC domains of FUS carrying the same mutations as (A) were exposed to mCherry:FUS hydrogels (left) and initial binding rates were measured (right). (C) A correlation plot between the transactivation activity and hydrogel binding rate of the individual LC mutants. Note that there is but one significant outlier indicated by a red circle. This is the “2A mutant” and described in more detail in the text and Figure 5.