Presence of O^2'-methylpseudouridine in the 18S + 26S ribosomal ribonucleates of wheat embryo

Abstract

With the Technical Assistance of Gladys M. Keddy ABSTRACT: 02/-Methylpseudouridine (i/m) has been identified as a constituent of wheat embryo cytosol rRNA. The corresponding 5'-nucleotide, p\fm, was recovered from snake venom hydrolysates of the 18S + 26S ribonucleates of wheat embryo. The identity of this nucleotide was established by its ultraviolet absorption spectra, chromatographic and electrophoretic properties, and conversion to i/'m by treatment with alkaline phosphatase. Control experiments have eliminated the possibility that contaminating tRNA could have been the source of the p\pm isolated from wheat embryo 18S + 26S rRNA. Alkaline hydrolysis of 18S + 26S rRNA released ipm in the form of an alkali-stable dinucleotide, ^m-Ap. Since the quantity of i/'in-Ap in alkaline hydrolysates (0.016 mol %) was equal to the amount of p^m found in venom hydrolysates (0.017 mol %), all of the \pm in wheat embryo 18S + 26S rRN A is apparently coni. he ribosomal RNA (rRNA) of various organisms is known to contain a small proportion of methylated nucleoside components,1 in which methyl groups are located either on the base or on the sugar (at the O2 ***' position) or on both (Attardi and Amaldi, 1970). Extensive analysis of the alkali-stable diand trinucleotide sequences of rRNA from a variety of organisms (Singh and Lane, 1964;Lane, 1965;

The ribosomal RNA of the trypanosomatid protozoan Crithidia fasciculata: physical characteristics and methylated sequences

“…Um-Ap, Im-Up) are single-copy sequences, whereas all other Nm-Np occur as multiple copies. A similar analysis of wheat embryo iRNA had previously suggested that the hypermodified sequences Cm-$p and $m-Ap were single-copy sequences in this RNA (19), and this was later confirmed by direct analysis of the individual wheat 26S and 18% rRNA9s (21 ). Interestingly, it would seem that the sequences Cm-$p and $m-Gp each occur in two copies in Crifhidi~z iRNA.…”

“…19) by the appropriate apparent molecular weights (Table I). A consistent molar ratio of 1.0:l.z bu:b) was found for the two high molecular weight RNA's present in undenatured total RNA or iRWA.…”

Identification of pseudouridine methyltransferase in Escherichia coli

“…The YbeA protein is hence a candidate for the only pseudouridine-specific methyltransferase in bacteria. Eukaryotic rRNAs also possess m 1 C (Brand et al 1978), Cm (Gray and Keddy 1974;Maden and Salim 1974), and the hypermodified derivative m 1 acp 3 C (Saponara and Enger 1974;Maden et al 1975). To our knowledge, no pseudouridine-specific methyltransferase has been described in eukaryotes.…”

“…edu/RNAmods/), hence making the corresponding m 3 Cmethyltransferase a likely candidate for the only pseudouridine-specific methyltransferase in bacteria. In eukaryotes, m 1 C, Cm, and m 1 acp 3 C are found (Gray and Keddy 1974;Maden and Salim 1974;Saponara and Enger 1974;Maden et al 1975;Brand et al 1978). So far, no pseudouridinespecific methyltransferases have been described.…”

Structural analysis of O2'-methyl-5-carbamoylmethyluridine, a newly discovered constituent of yeast transfer RNA

“…Brewer's yeast transfer R N A was purchased from Boehringer Mannheim. Analysis by polyacrylamide gel electrophoresis (Gray, 1974b) indicated that this material contained greater than 85% tRNA. and that D N A and high-molecular-weight rRNA were absent Other commercial products were Vipera russelli venom (Ross Allen Reptile Institute, Silver Springs, Fla.), Escherichia coli alkaline phosphatase (Worthington Biochemicals or Sigma Chemical Co.), and DEAE-cellulose (No.…”