RNA synthesis in growing and stationary cells of a culture of Scarlet Rose. Disproportionate synthesis of ribosomal subunits in the stationary state.
RNA synthesis has been investigated in resting and growing cells of a culture of Scarlet rose. The rates of messenger RNA (mRNA) and ribosomal RNA (rRNA) synthesis are five- and ten-fold higher, respectively, in the growing culture. In stationary phase cultures, newly synthesized 26S and 18S rRNA do not appear in the cytoplasm in equimolar amounts. Rather, the 26S/18S ratio of [3H]-uridine labeled rRNA of stationary cells ranged from 0.9 to 1.3 while the ratio of the corresponding fraction from growing cells was 1.6 to 2.0. A similar result was obtained when cells were labeled with [3H-CH3] methionine. Pulse chase experiments demonstrated that the nascent pre-rRNA in resting cells could be chased into polysomes. These data are interpreted to indicate that a major part of the regulation of rRNA synthesis in stationary cells is at the level of the processing of the rRNA transcript.
D002453:Cell Cycle; D002455:Cell Division; D009694:Nucleic Acid Precursors / Q000096:biosynthesis; D010944:Plants; D012313:RNA / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D012270:Ribosomes / Q000378:metabolism*
D009694:Nucleic Acid Precursors; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D012313:RNA