Figure 3.

The major cellular form of SNORD116 possesses a canonical 5′–3′ terminal stem structure. (A) Northern-blot hybridization with internally ³²P-labeled antisense mouse (left panel) or human (right panel) SNORD116 riboprobes using 10 µg of total RNA extracted from tissues as indicated above the gels. Two exposures (long and short) are shown for SNORD116. (B and C) Legends are as in Figure 2A and B. Note that the DNA sequencing ladder used to map precisely the 5′ end of SNORD116 was generated from a plasmid harboring a SNORD116 gene copy inserted downstream of T3 promoter, as indicated to the left of the gel. (D) Northern-blot hybridization to 5′-³²P end-labeled DNA oligonucleotides (sequences are given in Figure 1C) using 10 µg of total mouse or rat brain RNA. Only a very faint band was observed in rat but not in mouse brains (denoted by an asterisk, see also Figure 3A). Its relevance remains, however, questionable since both the 5′- and 3′-distal oligo-probes revealed it, an observation inconsistent with its apparent electrophoretic mobility. Note that the membrane first hybridized to m-snoRd116(4) was stripped and then re-used for hybridization to m-snoRD116(5).