Figure 4. Mass Spectrometry Experiments Identified Proteins that Bind Satellite RNAs.
(A) A diagram of the workflow.
(B) The protein-protein interaction network pulled down using satellite RNA is positively correlated with BRCA1 function (visualized with StringDB).
(C) RNA IP followed by western blotting confirmed the binding of satellite RNA to the proteins, as indicated, but not a control RNA.
(D) Co-IP followed by western blotting revealed (left) interaction between BRCA1 and Lamin B1, as shown by BRCA1 IP. BARD1 is shown as a positive control for BRCA1 interaction. Right: interactions between Lamin B1 and the indicated factors. GFP-Trap was used to pull down Lamin B1 in a LaminB1-GFP knockin U2OS cell line (the controls are IgG proteins from rabbits, mice, or rats instead of alpaca, from which the GFP antibody is derived).