UUCAC- and vera-dependent localization of VegT RNA in Xenopus oocytes.
Localized mRNAs are directed to their destinations by "localization elements" (LEs) in their 3'UTRs. LEs harbor multiple, functionally redundant localization "signals." These signals are poorly defined, hence it is unclear whether the signals-and their cognate factors-are unique to each RNA or employed generally. Five "E2s" (UUCACs) in the 366 nt Vg1 LE (VgLE) direct this transcript to the vegetal pole of Xenopus oocytes via the binding of a protein-Vera/Vg1RBP/ZBP. Here we show that a different vegetal RNA, VegT, employs the same signal and factor. Five E2s within a 440 nt subregion (VegT440) of the VegT 3'UTR predict its LE and are both necessary and sufficient (in the context of antisense VegT440) for directing localization. The E2s in VegT440 and VgLE function similarly to recruit Vera protein: (1) in both contexts, E2 nt substitutions partially (UU to AC) or completely (CA to UG) inhibit localization in accordance with the sequence selectivity of Vera protein for E2s; (2) VegT440 and VgLE crosscompete, in an E2-dependent manner, for localization and Vera binding; (3) injection of anti-Vera antibody into oocytes inhibits localization of both injected transcripts. These findings imply that general localization signals traffic diverse RNAs.
Kwon
Sunjong
S
Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
Abramson
Tatiana
T
Munro
Trent P
TP
John
Corinne M
CM
Köhrmann
Martin
M
Schnapp
Bruce J
BJ
D020413:3' Untranslated Regions / Q000502:physiology*; D000818:Animals; D001483:Base Sequence; D001692:Biological Transport; D006023:Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid / Q000502:physiology; D020825:T-Box Domain Proteins / Q000235:genetics*; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; D014982:Xenopus laevis
D020413:3' Untranslated Regions; C513103:GDF1 protein, Xenopus; D006023:Glycoproteins; D020825:T-Box Domain Proteins; D016212:Transforming Growth Factor beta; C103966:VegT protein, Xenopus; D029867:Xenopus Proteins