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Genes Dev

Title:		3'-UTR-dependent deadenylation by the yeast poly(A) nuclease
Author(s):		Lowell JE; Rudner DZ; Sachs AB;
Address:		"Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142"
Journal Title:		Genes Dev
Year:		1992
Volume:		6
Issue:		11
Page Number:		2088 - 2099
DOI:		10.1101/gad.6.11.2088
ISSN/ISBN:		0890-9369 (Print) 0890-9369 (Linking)
Abstract:		"Poly(A) tail removal is the first step in the degradation pathway for some mRNAs. The purified poly(A)-binding protein (PAB)-dependent poly(A) nuclease (PAN) from yeast removes mRNA poly(A) tails in vitro by a process similar to that observed in vivo. The exonucleolytic PAN degrades poly(A) and RNA bound by PAB, and can be activated by spermidine to degrade poly(A) in the absence of PAB. The shortening of the poly(A) tail down to 10-25 nucleotides and the terminal deadenylation of this short adenine tract are kinetically distinct reactions. Poly(A) shortening rates are stimulated by the yeast a-mating factor (MFA2) RNA 3' UTR sequence, and this occurs by switching PAN from a distributive to a more processive enzyme. Terminal deadenylation rates are also stimulated to different extents by various RNAs. Inversion of the MFA2 3' UTR sequence completely inhibits the terminal deadenylation reaction owing to the presence of an inhibitory element 70 nucleotides from the poly(A) tail. Other sequence elements inserted at a similar distance from the poly(A) tail also interfere with the reaction. These data suggest that the two phases of poly(A) degradation can be regulated by mRNA sequences, and they provide a mechanistic description of how this regulation could occur in vivo"
Keywords:		"Base Sequence Chromatography, Affinity DNA, Fungal/genetics Exoribonucleases/isolation & purification/*metabolism Kinetics Mating Factor Molecular Sequence Data Molecular Weight Oligodeoxyribonucleotides Osmolar Concentration Peptides/*genetics Plasmids P;"
Notes:		"MedlineLowell, J E Rudner, D Z Sachs, A B eng R29 GM43164/GM/NIGMS NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. 1992/11/01 Genes Dev. 1992 Nov; 6(11):2088-99. doi: 10.1101/gad.6.11.2088"