In vitro deadenylation of mammalian mRNA by a HeLa cell 3′ exonuclease

• Published in: The EMBO journal 1991-10, Vol.10 (10), p.3067-3071
• Main Authors: Aström, J., Aström, A., Virtanen, A.
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Base Sequence; Biological and medical sciences; Chromatography, Liquid; Clinical genetics; Deoxyribonucleotides; Dermatologi och venerologi, klinisk genetik, invärtesmedicin; Dermatology and venerology,clinical genetics, internal medicine; Electrophoresis; Enzymes and enzyme inhibitors; Exonucleases - metabolism; Fundamental and applied biological sciences. Psychology; HeLa Cells; Humans; Hydrolases; Klinisk genetik; Medical genetics; MEDICIN; MEDICINE; Medicinsk genetik; Molecular Sequence Data; Poly A - metabolism; RNA - metabolism; RNA, Messenger - metabolism; Substrate Specificity; Transcription, Genetic
• ISSN: 0261-4189; 1460-2075; 1460-2075
• DOI: 10.1002/j.1460-2075.1991.tb07858.x

We have identified a 3′ exonuclease in HeLa cell extracts which deadenylates mammalian mRNA and leaves the mRNA body intact after poly(A) removal. Only homopolymeric adenosine tails located at the 3′ end were efficiently removed by the exonuclease. The poly(A) removing activity did not require any specific sequences in the mRNA body either for poly(A) removal or for accumulation of the deadenylated mRNA. We conclude that the poly(A) removing activity is a 3′ exonuclease since (i) reaction intermediates gradually lose the poly(A) tail, (ii) degradation is prevented by the presence of a cordycepin residue at the 3′ end and (iii) RNAs having internally located poly(A) stretches are poor substrates for degradation. The possible involvement of the poly(A) removing enzyme in regulating mRNA translation and stability is discussed.