title: Acceleration of the rate of processing of 40 S pre-rRNA during Xenopus laevis embryogenesis.
abstract: Processing of 40 S pre-rRNA into 18 and 28 S mature rRNAs was studied in Xenopus embryonic cells by pulse-chase experiments using actinomycin D as a transcription-inhibitor. Gel electrophoretic analyses revealed that the rate of processing was accelerated due to a shortening of the half-life of 40 S pre-rRNA from 19 min at the gastrula stage to 9 min at and after the neurula stage. The step under developmental control appeared to be the cleavage of 40 S pre-rRNA into 18 S rRNA and the 34 S rRNA intermediate, since the time interval between the first detection of labeled 40 S pre-rRNA and 18 S rRNA was significantly shortened as development proceeded.
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000502:physiology; D005306:Fertilization; D007700:Kinetics; D008970:Molecular Weight; D009694:Nucleic Acid Precursors / Q000235:genetics*; D012322:RNA Precursors; D012335:RNA, Ribosomal / Q000235:genetics*; D014158:Transcription, Genetic; D014982:Xenopus laevis / Q000196:embryology*
chemical_list: D009694:Nucleic Acid Precursors; D012322:RNA Precursors; D012335:RNA, Ribosomal