title: Activation of ribosomal and messenger RNA synthesis in excised Jerusalem artichoke tuber slices.
abstract: RNA synthesis was studied in Jerusalem artichoke (Helianthus tuberosus L.) tuber slices immediately following excision and during the early period of aging in water. Incorporation of [(3)H]adenosine into RNA was detected as early as 20 min after excision. Measurement of the specific activities of RNA (cpm/μg) and of ATP showed that RNA synthesis proceeded at a constant rate for the first several hours of aging and then increased moderately. [(3)H]adenosine was incorporated into polysomes throughout the aging period examined. Sucrose gradient fractionation of EDTA-dissociated polysomes showed that during the first 2 h of aging most of this incorporation was not into ribosome subunits but into presumed mRNA. Autoradiographic analysis of [(3)H]adenosine labelled nuclei showed that this was caused, at least in part, by a delay in the onset of rRNA synthesis synthesized during this time chromatographed as poly(A)-RNA on oligo(dT)-cellulose, indicating that a large part of the mRNA was not polyadenylated.
authors.affiliation: Department of Biology ELBA, Carleton University, K1S 5B6, Ottawa, Ont., Canada.
authors.forename: H
authors.initials: H
authors.lastname: Byrne
authors.forename: G
authors.initials: G
authors.lastname: Setterfield