Effects of RNAi against protein components of snoRNPs on snoRNA expression levels. A. Northern blots of C/D box snoRNAs CeN40 and CeN65 after RNAi against C/D snoRNP component proteins Snu13, Nop1, Nop58 and Nop56. B. Northern blots of H/ACA box snoRNAs CeN46 and CeN104 after RNAi against H/ACA snoRNP component proteins Nop10, Cbf5, Nhp2 and Gar1.