FIGURE 5.

Depletion of snR35 blocks the formation of the hypermodified pseudouridine. (A) Biosynthetic pathway of the m1acp3Ψ hypermodification (Brand et al. 1978). (B) Primer extension analysis does not reveal the pseudouridylation status of the hypermodified site. RNA treated or not with CMC was subjected to primer extension analysis, with reaction products separated on an 8% polyacrylamide gel. (C) The chromatographic behavior is altered in cells depleted of snR35. An excised [³²P]18S rRNA fragment containing the hypermodified site and two additional pseudouridines from control (Con.) or (−)1a cells depleted of snR35 was digested by nuclease P1 and analyzed with TLC. The identities of the different nucleotide spots are indicated.