U1A polyadenylation inhibition element (PIE) explained

U1A polyadenylation inhibition element (PIE)
Symbol:	U1A_PIE
Rfam:	RF00460
Rna Type:	Cis-reg
Tax Domain:	Eukaryota

The U1A polyadenylation inhibition element (PIE) is an RNA element which is responsible for the regulation of the length of the polyA tail of the U1A protein pre-mRNA. The PIE is located in the U1A mRNA 3' UTR. PIE adopts a U-shaped structure, with binding sites for a single U1A protein at each bend and when complexed with the two proteins it blocks activity of poly(A) polymerase (PAP), and inhibits its activity.^{[1] [2]}

Notes and References

1. Clerte C, Hall KB . Global and local dynamics of the U1A polyadenylation inhibition element (PIE) RNA and PIE RNA-U1A complexes . Biochemistry . 43 . 42 . 13404–13415 . October 2004 . 15491147 . 10.1021/bi049117g .
2. Varani L, Gunderson SI, Mattaj IW, Kay LE, Neuhaus D, Varani G . The NMR structure of the 38 kDa U1A protein - PIE RNA complex reveals the basis of cooperativity in regulation of polyadenylation by human U1A protein . Nature Structural Biology . 7 . 4 . 329–335 . April 2000 . 10742179 . 10.1038/74101 . 13432764 .