Pontin and reptin are required for H/ACA RNP accumulation in vivo. (A) Western blots of low and high salt cell extracts from HeLa cells treated with the siRNAs to the targets indicated on top (in bold) and probed with antibodies to the proteins indicated on the right. Pontin and reptin knockdowns deplete pontin, fibrillarin, NAP57, and NHP2, but not SHQ1 nor tubulin or Nopp140 (lanes 3,4), whereas fibrillarin knockdown only depletes fibrillarin (lane 2). (B) Northern blots of total RNA extracted from cells treated with siRNAs to the targets indicated on top (in bold) and probed for RNAs indicated on the right. The amounts of the snoRNAs are each expressed as percent relative to the mock treated sample and were quantified relative to snRNA U1.
