The custom-made antibodies used in this study were generated in rabbits against either selected regions or full-length proteins, as described previously (Wang et al. 1996 (link); Yang et al. 2009a (link); Sabath et al. 2013 (link)). Antibodies against Drosophila Lsm10 and Lsm11 (Liu et al. 2006 (link); Nizami et al. 2010 (link)) were kindly provided by Joe Gall (Carnegie Institution for Science). Anti-Flag M2 (F3165) and anti-SmB (S0698) mouse monoclonal antibodies were from Sigma.