title: Very short-lived and stable mRNAs from resting human lymphocytes.
abstract: The kinetics of degradation of newly synthesized cytoplasmic poly(A)-bearing RNA have been examined in resting human lymphocytes. Two classes were identified, a very labile component with a half-life of less than 17 min and a stable component which remains apparently undiminished during 24 hr of observation. Both classes have molecular weights between 2.5 and 3.5 x 10(5) but the stable material has a narrower size distribution and a slightly lower average molecular weight than the short-lived component. The fate of stable RNA synthesized in the resting cell was also examined after growth stimulation with phytohemagglutinin after 2 and 6 hr of treatment. No transfer of stable material into the labile pool could be discerned; the amount of stable material remained constant. The existence of two species of mRNAs with different lifetimes in animal cells provides a potential means for regulation of protein synthesis by controlling the supply of specific messages. Furthermore, such a short-lived mRNA species may explain the observed disparity between the amount of poly(A)-bearing heterogeneous RNA produced in the nucleus and the amount of mature message found in the cytoplasm.
mesh_terms: D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D037102:Lectins / Q000494:pharmacology; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D008970:Molecular Weight; D011061:Poly A / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000096:biosynthesis; D013997:Time Factors
chemical_list: D037102:Lectins; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D011061:Poly A