Poly(A) metabolism in Xenopus laevis embryos: Substrate-specific and default poly(A) nuclease activities are mediated by two distinct complexes

• Published in: Biochimie Vol. 78; no. 6; pp. 399 - 407
• Main Authors: Paillard, L., Legagneux, V., Osborne, H.B.
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 1996; Elsevier
• Subjects: Animals; Chromatography, Gel; deadenylation; Development Biology; Electrophoresis, Polyacrylamide Gel; Embryology and Organogenesis; Female; Gene Expression Regulation, Developmental; Heparin; Heparin - pharmacology; Life Sciences; maternal mRNAs; Oocytes; Oocytes - enzymology; Poly A; poly(A) nuclease; Protein Biosynthesis; Putrescine; Putrescine - pharmacology; Ribonucleases; Ribonucleases - isolation & purification; Ribonucleases - metabolism; RNA, Messenger; RNA-Binding Proteins; RNA-Binding Proteins - metabolism; Spermidine; Spermidine - pharmacology; Substrate Specificity; Trans-Activators; translational regulation; Tumor Suppressor Protein p53; Tumor Suppressor Protein p53 - metabolism; Ultracentrifugation; Urea; Urea - pharmacology; Xenopus; Xenopus laevis; Xenopus laevis - embryology; UTR; SW; Xenopus laevis; poly(A) nuclease; maternal mRNAs; CPE; WP; translational regulation; PAN; deadenylation; MBT
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/0300-9084(96)84746-8

The metabolism of the poly(A) tail is a process important for the translational regulation of maternal mRNAs in Xenopus laevis oocytes and early embryos. Two poly(A) nuclease (PAN) activities have been described in Xenopus embryo or activated egg extracts (Legag neux et al (1995) RNA 1, 1001–1008). These activities (default PAN and EgPAN) are distinguishable by their deadenylation kinetics and their substrate specificities. In this report, we show that these activities display different sensitivities to biochemical treatments. Urea and to a lesser extent, spermidine, inhibit Egl'AN at concentrations which have no effect on default PAN. Heparin activates default PAN but inhibits EgPAN. When extracts are fractionated by ultracentrifugation, the default activity is recovered in one unique fraction, whereas two fractions must be combined to reconstitute the EgPAN activity. Moreover, these two deadenylation activities are separable by size exclusion chromatography under native conditions. We conclude that these two deadenylation activities are mediated by two protein complexes.