Wheat embryo ribonucleates. X. Metabolism of 3′-hydroxyl termini in the conserved mRNA and tRNA of imbibing wheat embryos

Publisher Website
Google Scholar
Abstract
There are conserved complements of rRNA, tRNA and mRNA in dry wheat embryos. Although early labeling of RNA is largely directed toward the synthesis of complete molecules of nascent rRNA and mRNA, there is also selective labeling at 3''-hydroxyl termini in conserved polynucleotides when dry wheat embryos are subjected to short-term (0.5 h) imbibition in a medium that contains tritium-labeled adenosine, guanosine, cytidine and uridine. Conserved tRNA is the principal mass component in NaCl-soluble RNA (sRNA) and most of the rapid labeling of sRNA (rl-sRNA) is a result of labeling at 3''-hydroxyl termini in conserved tRNA. By contrast, although conserved rRNA is the principal mass component in NaCl-insoluble RNA (iRNA), most of the labeled 3''-hydroxyl termini in rapidly labeled iRNA (rl-iRNA) do not appear to derive from rRNA. Although about 10% of the labeled 3''-hydroxyl termini in rl-iRNA originates in conserved poly(A)-rich mRNA, the available evidence leads to the conclusion that most of the labeled 3''-hydroxy termini in rl-iRNA originates in an unusual NaCl-insoluble fraction of conserved tRNA. During the course of extended imbibition, between 0.5 and 5 h, there are characteristic changes in the chain lengths and labeling patterns for 3''-hydroxyl terminal poly(A) sequences in mRNA. Analytical and physiological implications of these data are discussed.
Keywords

This publication has 12 references indexed in Scilit: