title: Substrate specificity of the exonuclease activity that degrades H4 histone mRNA.
abstract: We have investigated the substrate specificity of an exonuclease that degrades human H4 histone mRNA, using synthetic RNA templates incubated in a cell-free mRNA decay system (Ross, J., and Kobs, G. (1986) J. Mol. Biol. 188, 579-593). Five RNAs that lacked poly(A), including histone, were degraded rapidly in vitro. Polyadenylated histone mRNA was degraded at least 10-fold more slowly than unmodified histone mRNA. Double-stranded RNA and DNA were very stable. Single-stranded DNA was degraded approximately 20-fold more slowly than single-stranded, non-polyadenylated RNA, and RNA with a 3' phosphoryl group was degraded more slowly than RNA with a 3'-hydroxyl group. Uncapped RNAs were degraded rapidly in the unfractionated system but were stable in reactions containing a ribosomal high salt wash extract. Therefore, the exonuclease activity released from ribosomes by high salt extraction was separated from the enzyme(s) that degraded uncapped RNAs.
mesh_terms: D004247:DNA / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000378:metabolism; D005092:Exonucleases / Q000378:metabolism*; D005914:Globins / Q000235:genetics; D006657:Histones / Q000235:genetics*; D006801:Humans; D010957:Plasmids; D012333:RNA, Messenger / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D006657:Histones; D012333:RNA, Messenger; D005914:Globins; D004247:DNA; D005092:Exonucleases; D004262:DNA Restriction Enzymes