Biomaterial Database

Synthesis and translation of mRNA containing 5'-terminal 7-ethylguanosine cap. 1979

Y Furuichi, and M A Morgan, and A J Shatkin

Reovirus mRNA synthesis in vitro by the virion-associated RNA polymerase was only slightly (10 to 15%) diminished in the presence of 2 mM S-adenosylethionine. However, methyl group transfer from S-adenosylmethionine (0.05 mM) to the 5'-terminal cap structure, m7GpppGm in this mRNA was markedly inhibited (80%) under these conditions. Replacement of S-adenosylmethionine by S-adenosylethionine (5 mM) yielded mRNAs containing mainly (70%) 5'-terminal e7GpppGe and e7GpppG, but some of the products were unalkylated (5'-GpppG, ppG). The ethylated mRNAs, but not the unalkylated molecules, bound to wheat germ ribosomes and were translated essentially as well as the corresponding methylated mRNAs in wheat germ extracts and in nuclease-treated rabbit reticulocyte lysates. Protein synthesis directed by ethylated mRNAs in wheat germ extract was 80% decreased by 0.1 mM m7GMP. Under conditions of limited initiation, methylated mRNA bound to wheat germ ribosomes preferentially as compared to ethylated mRNA. The results document for the first time the synthesis of ethylated mRNA and support the hypothesis that N7-alkylation of the 5'-guanosine in caps, rather than methylation itself, is important for the enhancing effect of cap on the initiation of eukaryotic protein synthesis.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008745	Methylation	Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)	Methylations
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D012089	Mammalian orthoreovirus 3	A serotype of ORTHOREOVIRUS, MAMMALIAN causing serious pathology in laboratory rodents, characterized by diarrhea, oily coat, jaundice, and multiple organ involvement.	Reovirus 3,Mammalian Reovirus 3,Reovirus Type 3,Reovirus 3, Mammalian
D006151	Guanosine	A purine nucleoside that has guanine linked by its N9 nitrogen to the C1 carbon of ribose. It is a component of ribonucleic acid and its nucleotides play important roles in metabolism. (From Dorland, 28th ed)
D012314	RNA Cap Analogs	Analogs of RNA cap compounds which do not have a positive charge. These compounds inhibit the initiation of translation of both capped and uncapped messenger RNA.	RNA Cap Analogues,Analogs, RNA Cap,Analogues, RNA Cap,Cap Analogs, RNA,Cap Analogues, RNA
D012321	DNA-Directed RNA Polymerases	Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).	DNA-Dependent RNA Polymerases,RNA Polymerases,Transcriptases,DNA-Directed RNA Polymerase,RNA Polymerase,Transcriptase,DNA Dependent RNA Polymerases,DNA Directed RNA Polymerase,DNA Directed RNA Polymerases,Polymerase, DNA-Directed RNA,Polymerase, RNA,Polymerases, DNA-Dependent RNA,Polymerases, DNA-Directed RNA,Polymerases, RNA,RNA Polymerase, DNA-Directed,RNA Polymerases, DNA-Dependent,RNA Polymerases, DNA-Directed
D012333	RNA, Messenger	RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.	Messenger RNA,Messenger RNA, Polyadenylated,Poly(A) Tail,Poly(A)+ RNA,Poly(A)+ mRNA,RNA, Messenger, Polyadenylated,RNA, Polyadenylated,mRNA,mRNA, Non-Polyadenylated,mRNA, Polyadenylated,Non-Polyadenylated mRNA,Poly(A) RNA,Polyadenylated mRNA,Non Polyadenylated mRNA,Polyadenylated Messenger RNA,Polyadenylated RNA,RNA, Polyadenylated Messenger,mRNA, Non Polyadenylated
D012436	S-Adenosylmethionine	Physiologic methyl radical donor involved in enzymatic transmethylation reactions and present in all living organisms. It possesses anti-inflammatory activity and has been used in treatment of chronic liver disease. (From Merck, 11th ed)	AdoMet,Ademetionine,FO-1561,Gumbaral,S Amet,S-Adenosyl-L-Methionine,S-Adenosylmethionine Sulfate Tosylate,SAM-e,Samyr,FO 1561,FO1561,S Adenosyl L Methionine,S Adenosylmethionine,S Adenosylmethionine Sulfate Tosylate
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription