title: 5' terminal nucleotide sequences of the messenger RNA's of Dictyostelium discoideum.
abstract: As in the mRNA from all other eucaryotic cells examined, the 5' nucleotide in messenger RNA from Dictyostelium discoideum is linked by a 5'-5' triphosphate bridge to the unusual nucleoside 7-methyl guanosine. In mammalian cellular mRNA, the 5' terminal sequences have the general formula m7GpppXmpYp(m), where X and Y can be either purine or pyrimidine nucleotides and Y, as well as X, may contain a 2'0-methylated ribose. Although at least 32 5' terminal sequences are possible in cellular mRNA, only four are present in Dictyostelum mRNA. They are (I) m7GppppAp (65%); (II) m7GpppGp (10%); (III) m7GpppAmpAp (10%); (IV m7GpppAp (65%); (II) m7gpppGp (10%); (III) m7GpppAmpAp (10%); (IV) m7GpppAmpUp (10%). Sequences I and II are simpler than those previously reported for mammalian cells because they lack 2'0-methylated nucleosides. Another difference is that in all Dictyostelium mRNAs. the nucleoside X is a purine. The nucleoside 6-methyl adenosine which is found internal to the 5' end of the mRNA of mammalian cells is not detectable in Dictyostelium mRNA. Thus neither 2'0-methylated nucleotides nor 6-methyl adenosine can represent sites for processing of a primary nuclear transript to yield mRNA.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000032:analysis; D000469:Alkaline Phosphatase; D001483:Base Sequence; D004023:Dictyostelium / Q000032:analysis*; D004586:Electrophoresis; D006150:Guanine Nucleotides / Q000032:analysis; D009235:Myxomycetes / Q000032:analysis*; D009843:Oligoribonucleotides / Q000032:analysis; D010727:Phosphoric Diester Hydrolases; D012333:RNA, Messenger / Q000032:analysis*; D012260:Ribonucleases
chemical_list: D006150:Guanine Nucleotides; D009843:Oligoribonucleotides; D012333:RNA, Messenger; D012260:Ribonucleases; D000469:Alkaline Phosphatase; D010727:Phosphoric Diester Hydrolases; D000241:Adenosine