5'-Terminal cap structures of oligo(uridylic acid)-containing messenger ribonucleic acid from HeLa cells: comparison with other ribonucleic acid subpopulations.
The 5'-terminal cap structures of 32P-labeled oligo(uridylic acid)-containing messenger ribonucleic acid [oligo(U+)mRNA] isolated from HeLa cell polyadenylated [poly(A+)] mRNA were analyzed and compared to those of the poly(A+) mRNA. A method employing P1 nuclease, alkaline phosphatase, and adsorption to activated charcoal showed that the types of cap core (m7 GpppXm) in oligo(U+) mRNA were essentially identical with those in poly(A+) mRNA. Analysis of RNase T2 digestion products of oligo(U+) mRNA demonstrated the presence of both cap 1 (m7GpppXmpYp) and cap 2 (m7GpppXmpYmpZp) in this subpopulation, confirming its cytoplasmic location. The base compositions of these two types of caps were different from each other and nonrandom but did not differ significantly between oligo(U+) and poly(A+) m RNA. The only observed difference between the mRNA populations was a higher ratio of cap 1 and cap 2 in the former. Possible implications of these findings for the relationship between oligo(U+) mRNA and poly(A+) mRNA are discussed.
D006367:HeLa Cells / Q000032:analysis; D006801:Humans; D011061:Poly A / Q000032:analysis; D012313:RNA / Q000302:isolation & purification*; D012315:RNA Caps / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis*; D014500:Uracil Nucleotides / Q000032:analysis*
D012315:RNA Caps; D012333:RNA, Messenger; D014500:Uracil Nucleotides; C032369:oligo(U+)RNA; D011061:Poly A; D012313:RNA