Nazar R N, Owens T W, Sitz T O, Busch H
J Biol Chem. 1975 Apr 10;250(7):2475-81.
Evidence that 32 S nRNA contains 5.8 S rRNA was provided by studies on specific oligonucleotide sequences of these RNA species. Purified 32P-labeled 5.8 and 28 S rRNA and 32 S RNA were digested with T-1 ribonuclease, and the products were fractionated according to chain length by chromatography on DEAE-Sephadex A-25 at neutral pH. The oligonucleotides in Peak 8 were treated with alkaline phosphatase and the products were separated by two-dimensional electrophoresis on cellulose acetate at pH 3.5 and DEAE-paper in 7% formic acid. Seven unique oligonucleotide markers for 5.8 S rRNA including the methylated octanucleotide A-A-U-U-Gm-G-A-Gp were present in 32 S RNA but were not found in 28 S rRNA, indicating that 5.8 S rRNA is directly derived from the 32 S nucleolar precursor. These studies confirm a maturation pathway for rRNA species in which 32 S nucleolar RNA is a precursor of 5.8 S rRNA as well as 28 S rRNA.
对这些RNA种类的特定寡核苷酸序列的研究提供了32 S核仁RNA包含5.8 S核糖体RNA的证据。用T-1核糖核酸酶消化纯化的32P标记的5.8和28 S核糖体RNA以及32 S核仁RNA，产物在中性pH下于DEAE-葡聚糖A-25上进行层析，根据链长进行分级分离。对峰8中的寡核苷酸用碱性磷酸酶处理，产物在pH 3.5的醋酸纤维素和7%甲酸中的DEAE-纸上进行二维电泳分离。32 S核仁RNA中存在7种5.8 S核糖体RNA的独特寡核苷酸标记，包括甲基化八核苷酸A-A-U-U-Gm-G-A-Gp，但在28 S核糖体RNA中未发现，这表明5.8 S核糖体RNA直接来源于32 S核仁前体。这些研究证实了核糖体RNA种类的成熟途径，其中32 S核仁RNA是5.8 S核糖体RNA以及28 S核糖体RNA的前体。
