First published online August 25, 2006
Development 133, 1804e (2006)
© The Company of Biologists Limited
Translational regulation moves upstream
Gene expression during development is regulated both transcriptionally and
translationally; however, relatively few examples of translational regulation
are known. On p.
3575, Imai and colleagues describe for the first time how an upstream
open reading frame (uORF) mediates translational control during plant
development. Loss-of-function mutants of Arabidopsis ACAULIS 5
(ACL5), which encodes spermine synthase, have a dwarf phenotype
because of a defect in stem elongation. To find out how ACL5
regulates stem elongation, the researchers isolated a dominant suppressor
mutant of the acl5 phenotype - sac51-d. They show that
sac51-d disrupts a short uORF of SAC51, which encodes a bHLH
transcription factor. Other experiments indicate that this disruption might
increase the translation of SAC51. Thus, the researchers suggest that
the uORF-encoded protein normally prevents the initiation of SAC51
translation, and that ACL5 acts directly or indirectly (possibly
through spermine's effects on protein synthesis) to activate SAC51
translation and subsequent stem elongation.
Related articles in Development:
- The dwarf phenotype of the Arabidopsis acl5 mutant is suppressed by a mutation in an upstream ORF of a bHLH gene
- Akihiro Imai, Yoshie Hanzawa, Mio Komura, Kotaro T. Yamamoto, Yoshibumi Komeda, and Taku Takahashi
Development 2006 133: 3575-3585.
[Abstract]
[Full Text]
