The Fed-1 (CAUU)4 element is a 5' UTR dark-responsive mRNA instability element that functions independently of dark-induced polyribosome dissociation.
Darkness rapidly induces a decline in the stability and translation of the pea Ferredoxin-1 (Fed-1) mRNA in transgenic tobacco. Direct half-life measurement showed that mutation of the (CAUU)4 stabilizes Fed-1 mRNA in the dark. (CAUU)1, a feature more common in plant 5' UTRs than (CAUU)4, confers slight light-responsive mRNA accumulation. At least three but less than 11 CAUU repeats near the 5' end of the 5' UTR are required for full light-responsive accumulation. Furthermore, 26 nt of the 5' UTR, including the (CAUU)4 repeat, is sufficient to confer a significant approximately 2.5-fold increase in light-regulated mRNA accumulation when fused to the 5' end of a heterologous plant mRNA. A mutation of the (CAUU)4 repeat that compromises light-regulated mRNA stability changes in vitro the accessibility of the region to ribonuclease V1 and ribonuclease A suggesting the geometry formed by the repeat may be important for instability. Finally, dark-induced Fed-1 mRNA instability occurs even when most of the mRNA is retained on polyribosomes, and thus is likely an independent event regulated by darkness.
Bhat
Sumana
S
Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA.
Tang
Li
L
Krueger
Angela D
AD
Smith
Christopher L
CL
Ford
Sharon R
SR
Dickey
Lynn F
LF
Petracek
Marie E
ME
D020121:5' Untranslated Regions / Q000235:genetics*; D001483:Base Sequence; D003624:Darkness; D005288:Ferredoxins / Q000235:genetics*; D006207:Half-Life; D008027:Light; D018895:Microsatellite Repeats / Q000235:genetics; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000235:genetics; D030821:Plants, Genetically Modified; D011132:Polyribosomes / Q000378:metabolism* / Q000528:radiation effects; D020871:RNA Stability / Q000235:genetics / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics
D020121:5' Untranslated Regions; D005288:Ferredoxins; D012333:RNA, Messenger