Probable cloning artefacts previously interpreted as unusual leader sequences of rodent ornithine decarboxylase mRNAs--a cautionary tale.
Messenger RNAs that have structurally unusual 5' leaders attract interest and provoke conjecture. Cloning and sequencing of two rodent ornithine decarboxylase (ODC) cDNAs, those for mouse [Kahana and Nathans, Proc. Natl. Acad. Sci. USA 82 (1985) 1673-1677] and, recently as published in this journal, for rat [Van Kranen et al., Gene 60 (1987) 145-155], have indicated the presence of such features. In both cases, the leader is unusually long and contains multiple AUG start codons preceding that which encodes the N terminus of the protein. In addition, the leader of the rat clone contains a 54-nt perfect inverted repeat. Because ODC expression appears to be regulated translationally, functional implications immediately suggest themselves. Certain unusual features of the mouse cDNA have proven artefactual [Brabant et al., Proc. Natl. Acad. Sci. USA 85 (1988) 2200-2204; Katz and Kahana, J. Biol. Chem. 263 (1988) 7604-7609]. It is likely that the putative leader sequence of rat ODC cDNA also resulted from a cloning artefact.
Coffino
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Department of Medicine, University of California, San Francisco 94143.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods*; D003062:Codon; D004247:DNA / Q000235:genetics; D005796:Genes; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D014176:Protein Biosynthesis; D021382:Protein Sorting Signals / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D014158:Transcription, Genetic
D003062:Codon; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D004247:DNA; D009955:Ornithine Decarboxylase