title: H4 histone messenger RNA decay in cell-free extracts initiates at or near the 3' terminus and proceeds 3' to 5'.
abstract: The relative decay of four human messenger RNAs, gamma globin, delta globin, c-myc and H4 histone, were compared in a cell-free system. Under appropriate conditions, they are degraded in vitro in approximately the same relative order as in vivo: histone faster than c-myc and delta globin faster than gamma globin. Degradation of polysome-associated H4 histone mRNA and of deproteinized histone mRNA begins at or near the 3' terminus. At least a portion of the mRNA then continues to be degraded in a 3' to 5' direction. Discrete 3'-terminal degradation hold-up points are observed, suggesting that 3' to 5' degradation occurs non-uniformly. Cycloheximide and puromycin inhibit protein synthesis but do not affect the rate or directionality of histone mRNA decay in vitro. We conclude that the rate-limiting step in H4 histone mRNA decay occurs at or near the 3' terminus and that at least a portion of the mRNA molecule is subsequently degraded 3' to 5', probably via a processive exonuclease.
mesh_terms: D003513:Cycloheximide / Q000494:pharmacology; D005914:Globins / Q000235:genetics; D006657:Histones / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D009693:Nucleic Acid Hybridization; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D011691:Puromycin / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D006657:Histones; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D011691:Puromycin; D005914:Globins; D003513:Cycloheximide