AUF1 binding affinity to A+U-rich elements correlates with rapid mRNA degradation.
Rapid degradation of many labile mRNAs is regulated in part by an A + U-rich element (ARE) in their 3'-untranslated regions. Extensive mutational analyses of various AREs have identified important components of the ARE, such as the nonamer motif UUAUUUAUU, two copies of which serve as a potent mRNA destabilizer. To investigate the roles of trans-acting factors in ARE-directed mRNA degradation, we previously purified and molecularly cloned the RNA-binding protein AUF1 and demonstrated that both cellular and recombinant AUF1 bind specifically to AREs as shown by UV cross-linking assays in vitro. In the present work, we have examined the in vitro RNA-binding properties of AUF1 using gel mobility shift assays with purified recombinant His6-AUF1 fusion protein. We find that ARE binding affinities of AUF1 correlate with the potency of an ARE to direct degradation of a heterologous mRNA. These results support a role for AUF1 in ARE-directed mRNA decay that is based upon its affinity for different AREs.
DeMaria
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Department of Microbiology and Immunology, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, North Carolina 27157-1064, USA.
Brewer
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D000225:Adenine / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D; D006639:Histidine / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data; D011485:Protein Binding; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D014529:Uridine / Q000378:metabolism*
D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D; D016760:Proto-Oncogene Proteins c-fos; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D006639:Histidine; D000225:Adenine; D014529:Uridine