Tristetraprolin and its family members can promote the cell-free deadenylation of AU-rich element-containing mRNAs by poly(A) ribonuclease.
Eukaryotic mRNA stability can be influenced by AU-rich elements (AREs) within mRNA primary sequences. Tristetraprolin (TTP) is a CCCH tandem zinc finger protein that binds to ARE-containing transcripts and destabilizes them, apparently by first promoting the removal of their poly(A) tails. We developed a cell-free system in which TTP and its related proteins stimulated the deadenylation of ARE-containing, polyadenylated transcripts. Transcript deadenylation was not stimulated when a mutant TTP protein was used that was incapable of RNA binding, nor when a mutant ARE was present that did not bind TTP. The ability of TTP to promote transcript deadenylation required Mg(2+), but not ATP or prior capping of the RNA substrate. Cotransfection and additivity studies with the poly(A) RNase (PARN) demonstrated that TTP promoted the ability of this enzyme to deadenylate ARE-containing, polyadenylated transcripts, while having no effect on transcripts lacking an ARE. There was no effect of TTP to act synergistically with enzymatically inactive PARN mutants. We conclude that TTP can promote the deadenylation of ARE-containing, polyadenylated substrates by PARN. This interaction may be responsible for the ability of TTP and its family members to promote the deadenylation of such transcripts in intact cells.
Laboratory of Signal Transduction. Office of Clinical Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA.
Wi S
WS
Lai
Elizabeth A
EA
Kennington
Perry J
PJ
Blackshear
D000225:Adenine / Q000378:metabolism*; D001482:Base Composition; D002460:Cell Line; D002474:Cell-Free System; D004268:DNA-Binding Proteins; D005095:Exoribonucleases / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D051816:Tristetraprolin; D014498:Uracil / Q000378:metabolism*; D016335:Zinc Fingers
D000225:Adenine; D004268:DNA-Binding Proteins; D005095:Exoribonucleases; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D051816:Tristetraprolin; D014498:Uracil; C497552:ZFP36 protein, human